fbpx
Wikipedia

Molecular Structure of Nucleic Acids: A Structure for Deoxyribose Nucleic Acid

"Molecular Structure of Nucleic Acids: A Structure for Deoxyribose Nucleic Acid" was the first article published to describe the discovery of the double helix structure of DNA, using X-ray diffraction and the mathematics of a helix transform. It was published by Francis Crick and James D. Watson in the scientific journal Nature on pages 737–738 of its 171st volume (dated 25 April 1953).[1][2]

Diagramatic representation of the key structural features of the DNA double helix. This figure does not depict B-DNA.

This article is often termed a "pearl" of science because it is brief and contains the answer to a fundamental mystery about living organisms. This mystery was the question of how it is possible that genetic instructions are held inside organisms and how they are passed from generation to generation. The article presents a simple and elegant solution, which surprised many biologists at the time who believed that DNA transmission was going to be more difficult to deduce and understand. The discovery had a major impact on biology, particularly in the field of genetics, enabling later researchers to understand the genetic code.

Evolution of molecular biology edit

The application of physics and chemistry to biological problems led to the development of molecular biology, which is particularly concerned with the flow and consequences of biological information from DNA to proteins. The discovery of the DNA double helix made clear that genes are functionally defined parts of DNA molecules, and that there must be a way for cells to translate the information in DNA to specific amino acids, which make proteins.

Linus Pauling was a chemist who was very influential in developing an understanding of the structure of biological molecules. In 1951, Pauling published the structure of the alpha helix, a fundamentally important structural component of proteins. In early 1953, Pauling published a triple helix model of DNA, which subsequently turned out to be incorrect.[3] Both Crick, and particularly Watson, thought that they were racing against Pauling to discover the structure of DNA.

Max Delbrück was a physicist who recognized some of the biological implications of quantum physics. Delbruck's thinking about the physical basis of life stimulated Erwin Schrödinger to write What Is Life?. Schrödinger's book was an important influence on Crick and Watson. Delbruck's efforts to promote the "Phage Group" (exploring genetics by way of the viruses that infect bacteria) was important in the early development of molecular biology in general and the development of Watson's scientific interests in particular.[4]

Crick, Watson, and Maurice Wilkins won the Nobel Prize for Medicine in recognition of their discovery of the DNA double helix.

DNA structure and function edit

It is not always the case that the structure of a molecule is easy to relate to its function. What makes the structure of DNA so obviously related to its function was described modestly at the end of the article: "It has not escaped our notice that the specific pairing we have postulated immediately suggests a possible copying mechanism for the genetic material".

 
DNA replication. The two base-pair complementary chains of the DNA molecule allow replication of the genetic instructions.

The "specific pairing" is a key feature of the Watson and Crick model of DNA, the pairing of nucleotide subunits.[5] In DNA, the amount of guanine is equal to cytosine and the amount of adenine is equal to thymine. The A:T and C:G pairs are structurally similar. In particular, the length of each base pair is the same and they fit equally between the two sugar-phosphate backbones. The base pairs are held together by hydrogen bonds, a type of chemical attraction that is easy to break and easy to reform. After realizing the structural similarity of the A:T and C:G pairs, Watson and Crick soon produced their double helix model of DNA with the hydrogen bonds at the core of the helix providing a way to unzip the two complementary strands for easy replication: the last key requirement for a likely model of the genetic molecule.

Indeed, the base-pairing did suggest a way to copy a DNA molecule. Just pull apart the two sugar-phosphate backbones, each with its hydrogen bonded A, T, G, and C components. Each strand could then be used as a template for assembly of a new base-pair complementary strand.

Future considerations edit

 
Watson and Crick used many aluminium templates like this one, which is the single base Adenine (A), to build a physical model of DNA in 1953.

When Watson and Crick produced their double helix model of DNA, it was known that most of the specialized features of the many different life forms on Earth are made possible by proteins. Structurally, proteins are long chains of amino acid subunits. In some way, the genetic molecule, DNA, had to contain instructions for how to make the thousands of proteins found in cells. From the DNA double helix model, it was clear that there must be some correspondence between the linear sequences of nucleotides in DNA molecules to the linear sequences of amino acids in proteins. The details of how sequences of DNA instruct cells to make specific proteins was worked out by molecular biologists during the period from 1953 to 1965. Francis Crick played an integral role in both the theory and analysis of the experiments that led to an improved understanding of the genetic code.[6]

Consequences edit

Other advances in molecular biology stemming from the discovery of the DNA double helix eventually led to ways to sequence genes. James Watson directed the Human Genome Project at the National Institutes of Health.[7] The ability to sequence and manipulate DNA is now central to the biotechnology industry and modern medicine. The austere beauty of the structure and the practical implications of the DNA double helix combined to make Molecular structure of Nucleic Acids; A Structure for Deoxyribose Nucleic Acid one of the most prominent biology articles of the twentieth century.

Collaborators and controversy edit

Although Watson and Crick were first to put together all the scattered fragments of information that were required to produce a successful molecular model of DNA, their findings had been based on data collected by researchers in several other laboratories. For example, they drew on published research relating to the discovery of Hydrogen bonds in DNA by John Masson Gulland, Denis Jordan and their colleagues at University College Nottingham in 1947.[8][9][10] However the discovery of the DNA double helix also used a considerable amount of material from the unpublished work of Rosalind Franklin, A.R. Stokes, Maurice Wilkins, and H.R. Wilson at King's College London. Key data from Wilkins, Stokes, and Wilson, and, separately, by Franklin and Gosling, were published in two separate additional articles in the same issue of Nature with the article by Watson and Crick.[11][12] The article by Watson and Crick acknowledged that they had been "stimulated" by experimental results from the King's College researchers, and a similar acknowledgment was published by Wilkins, Stokes, and Wilson in the following three-page article.

In 1968, Watson published a highly controversial autobiographical account of the discovery of the double-helical, molecular structure of DNA called The Double Helix, which was not publicly accepted either by Crick or Wilkins.[13] Furthermore, Erwin Chargaff also printed a rather "unsympathetic review" of Watson's book in the 29 March 1968 issue of Science. In the book, Watson stated among other things that he and Crick had access to some of Franklin's data from a source that she was not aware of, and also that he had seen—without her permission—the B-DNA X-ray diffraction pattern obtained by Franklin and Gosling in May 1952 at King's in London. In particular, in late 1952, Franklin had submitted a progress report to the Medical Research Council, which was reviewed by Max Perutz, then at the Cavendish Laboratory of the University of Cambridge. Watson and Crick also worked in the MRC-supported Cavendish Laboratory in Cambridge whereas Wilkins and Franklin were in the MRC-supported laboratory at King's in London. Such MRC reports were not usually widely circulated, but Crick read a copy of Franklin's research summary in early 1953.[13][14]

Perutz's justification for passing Franklin's report about the crystallographic unit of the B-DNA and A-DNA structures to both Crick and Watson was that the report contained information which Watson had heard before, in November 1951, when Franklin talked about her unpublished results with Raymond Gosling during a meeting arranged by M.H.F. Wilkins at King's College, following a request from Crick and Watson;[15] Perutz said he had not acted unethically because the report had been part of an effort to promote wider contact between different MRC research groups and was not confidential.[16] This justification would exclude Crick, who was not present at the November 1951 meeting, yet Perutz also gave him access to Franklin's MRC report data. Crick and Watson then sought permission from Cavendish Laboratory head William Lawrence Bragg, to publish their double-helix molecular model of DNA based on data from Franklin and Wilkins.

By November 1951, Watson had acquired little training in X-ray crystallography, by his own admission, and thus had not fully understood what Franklin was saying about the structural symmetry of the DNA molecule.[14] Crick, however, knowing the Fourier transforms of Bessel functions that represent the X-ray diffraction patterns of helical structures of atoms, correctly interpreted further one of Franklin's experimental findings as indicating that DNA was most likely to be a double helix with the two polynucleotide chains running in opposite directions. Crick was thus in a unique position to make this interpretation because he had formerly worked on the X-ray diffraction data for other large molecules that had helical symmetry similar to that of DNA. Franklin, on the other hand, rejected the first molecular model building approach proposed by Crick and Watson: the first DNA model, which in 1952 Watson presented to her and to Wilkins in London, had an obviously incorrect structure with hydrated charged groups on the inside of the model, rather than on the outside. Watson explicitly admitted this in his book The Double Helix.[14]

See also edit

References edit

  1. ^ Watson JD, Crick FH (April 1953). "Molecular structure of nucleic acids; a structure for deoxyribose nucleic acid". Nature. 171 (4356): 737–738. Bibcode:1953Natur.171..737W. doi:10.1038/171737a0. PMID 13054692. S2CID 4253007.
  2. ^ Cochran W, Crick FHC and Vand V. (1952) "The Structure of Synthetic Polypeptides. I. The Transform of Atoms on a Helix", Acta Crystallogr., 5, 581–586.
  3. ^ Pauling L, Corey RB (1953). "A Proposed Structure for the Nucleic Acids". PNAS. 39 (2): 84–97. Bibcode:1953PNAS...39...84P. doi:10.1073/pnas.39.2.84. PMC 1063734. PMID 16578429.
  4. ^ Judson, Horace Freeland (1979). Eighth Day of Creation: Makers of the Revolution in Biology. New York: Simon & Schuster. ISBN 9780671254100.
  5. ^ Discover the rules of DNA base pairing with an online simulator.
  6. ^ Perutz MF, Randall JT, Thomson L, Wilkins MH, Watson JD (June 1969). "DNA helix". Science. 164 (3887): 1537–9. Bibcode:1969Sci...164.1537W. doi:10.1126/science.164.3887.1537. PMID 5796048.
  7. ^ "History – Historic Figures: Watson and Crick (1928- )". BBC. Retrieved 15 June 2014.
  8. ^ JM Gulland; DO Jordan; HF Taylor; (1947) Deoxypentose nucleic acids; Part II electrometric titration of the acidic and the basic groups of the deoxypentose nucleic acid of calf thymus. J Chem Soc. 1947; 25:1131-41.
  9. ^ Creeth, J.M., Gulland, J.M. and Jordan, D.O. (1947) Deoxypentose nucleic acids. Part III. Viscosity and streaming birefringence of solutions of the sodium salt of the deoxypentose nucleic acid of calf thymus. J. Chem. Soc. 1947,25 1141–1145
  10. ^ Watson, James D., 2012 The Annotated and Illustrated Double Helix, Ed. Gann & Witkowski, Simon & Schuster, New York (pp196-7)
  11. ^ Franklin R, Gosling RG (25 April 1953). "Molecular configuration in sodium thymonucleate" (PDF). Nature. 171 (4356): 740–741. Bibcode:1953Natur.171..740F. doi:10.1038/171740a0. PMID 13054694. S2CID 4268222.
  12. ^ Wilkins MH, Stokes AR, Wilson HR (25 April 1953). "Molecular structure of deoxypentose nucleic acids" (PDF). Nature. 171 (4356): 738–740. Bibcode:1953Natur.171..738W. doi:10.1038/171738a0. PMID 13054693. S2CID 4280080.
  13. ^ a b Beckwith, Jon (2003). "Double Take on the Double Helix". In Victor K. McElheny (ed.). Watson and DNA: Making a Scientific Revolution. Cambridge, MA: Perseus Publishing. p. 363. ISBN 978-0-738-20341-6. OCLC 51440191.
  14. ^ a b c Watson, James D. (1980). The Double Helix: A Personal Account of the Discovery of the Structure of DNA. Atheneum. ISBN 978-0-689-70602-8. (first published in 1968)
  15. ^ Sayre, Anne (1975). Rosalind Franklin and DNA. New York: Norton.
  16. ^ Perutz MF, Randall JT, Thomson L, Wilkins MH, Watson JD (27 June 1969). "DNA helix". Science. 164 (3887): 1537–1539. Bibcode:1969Sci...164.1537W. doi:10.1126/science.164.3887.1537. PMID 5796048.

Bibliography edit

External links edit

  • Annotated copy of the article from San Francisco's Exploratorium
  • Access Excellence Classic Collection article on DNA structure.
  • Linus Pauling and the Race for DNA: A Documentary History

Online versions edit

  • Online version (Original text) at nature.com
  • National Library of Medicine's PDF copy in the Francis Crick Documents Collection.
  • Commemorative HTML version Am J Psychiatry 160:623-624, April 2003.

molecular, structure, nucleic, acids, structure, deoxyribose, nucleic, acid, first, article, published, describe, discovery, double, helix, structure, using, diffraction, mathematics, helix, transform, published, francis, crick, james, watson, scientific, jour. Molecular Structure of Nucleic Acids A Structure for Deoxyribose Nucleic Acid was the first article published to describe the discovery of the double helix structure of DNA using X ray diffraction and the mathematics of a helix transform It was published by Francis Crick and James D Watson in the scientific journal Nature on pages 737 738 of its 171st volume dated 25 April 1953 1 2 Diagramatic representation of the key structural features of the DNA double helix This figure does not depict B DNA This article is often termed a pearl of science because it is brief and contains the answer to a fundamental mystery about living organisms This mystery was the question of how it is possible that genetic instructions are held inside organisms and how they are passed from generation to generation The article presents a simple and elegant solution which surprised many biologists at the time who believed that DNA transmission was going to be more difficult to deduce and understand The discovery had a major impact on biology particularly in the field of genetics enabling later researchers to understand the genetic code Contents 1 Evolution of molecular biology 2 DNA structure and function 2 1 Future considerations 2 2 Consequences 3 Collaborators and controversy 4 See also 5 References 6 Bibliography 7 External links 7 1 Online versionsEvolution of molecular biology editThe application of physics and chemistry to biological problems led to the development of molecular biology which is particularly concerned with the flow and consequences of biological information from DNA to proteins The discovery of the DNA double helix made clear that genes are functionally defined parts of DNA molecules and that there must be a way for cells to translate the information in DNA to specific amino acids which make proteins Linus Pauling was a chemist who was very influential in developing an understanding of the structure of biological molecules In 1951 Pauling published the structure of the alpha helix a fundamentally important structural component of proteins In early 1953 Pauling published a triple helix model of DNA which subsequently turned out to be incorrect 3 Both Crick and particularly Watson thought that they were racing against Pauling to discover the structure of DNA Max Delbruck was a physicist who recognized some of the biological implications of quantum physics Delbruck s thinking about the physical basis of life stimulated Erwin Schrodinger to write What Is Life Schrodinger s book was an important influence on Crick and Watson Delbruck s efforts to promote the Phage Group exploring genetics by way of the viruses that infect bacteria was important in the early development of molecular biology in general and the development of Watson s scientific interests in particular 4 Crick Watson and Maurice Wilkins won the Nobel Prize for Medicine in recognition of their discovery of the DNA double helix DNA structure and function editThis section needs additional citations for verification Please help improve this article by adding citations to reliable sources in this section Unsourced material may be challenged and removed Find sources Molecular Structure of Nucleic Acids A Structure for Deoxyribose Nucleic Acid news newspapers books scholar JSTOR April 2017 Learn how and when to remove this template message It is not always the case that the structure of a molecule is easy to relate to its function What makes the structure of DNA so obviously related to its function was described modestly at the end of the article It has not escaped our notice that the specific pairing we have postulated immediately suggests a possible copying mechanism for the genetic material nbsp DNA replication The two base pair complementary chains of the DNA molecule allow replication of the genetic instructions The specific pairing is a key feature of the Watson and Crick model of DNA the pairing of nucleotide subunits 5 In DNA the amount of guanine is equal to cytosine and the amount of adenine is equal to thymine The A T and C G pairs are structurally similar In particular the length of each base pair is the same and they fit equally between the two sugar phosphate backbones The base pairs are held together by hydrogen bonds a type of chemical attraction that is easy to break and easy to reform After realizing the structural similarity of the A T and C G pairs Watson and Crick soon produced their double helix model of DNA with the hydrogen bonds at the core of the helix providing a way to unzip the two complementary strands for easy replication the last key requirement for a likely model of the genetic molecule Indeed the base pairing did suggest a way to copy a DNA molecule Just pull apart the two sugar phosphate backbones each with its hydrogen bonded A T G and C components Each strand could then be used as a template for assembly of a new base pair complementary strand Future considerations edit nbsp Watson and Crick used many aluminium templates like this one which is the single base Adenine A to build a physical model of DNA in 1953 When Watson and Crick produced their double helix model of DNA it was known that most of the specialized features of the many different life forms on Earth are made possible by proteins Structurally proteins are long chains of amino acid subunits In some way the genetic molecule DNA had to contain instructions for how to make the thousands of proteins found in cells From the DNA double helix model it was clear that there must be some correspondence between the linear sequences of nucleotides in DNA molecules to the linear sequences of amino acids in proteins The details of how sequences of DNA instruct cells to make specific proteins was worked out by molecular biologists during the period from 1953 to 1965 Francis Crick played an integral role in both the theory and analysis of the experiments that led to an improved understanding of the genetic code 6 Consequences edit Other advances in molecular biology stemming from the discovery of the DNA double helix eventually led to ways to sequence genes James Watson directed the Human Genome Project at the National Institutes of Health 7 The ability to sequence and manipulate DNA is now central to the biotechnology industry and modern medicine The austere beauty of the structure and the practical implications of the DNA double helix combined to make Molecular structure of Nucleic Acids A Structure for Deoxyribose Nucleic Acid one of the most prominent biology articles of the twentieth century Collaborators and controversy editMain article King s College London DNA Controversy Although Watson and Crick were first to put together all the scattered fragments of information that were required to produce a successful molecular model of DNA their findings had been based on data collected by researchers in several other laboratories For example they drew on published research relating to the discovery of Hydrogen bonds in DNA by John Masson Gulland Denis Jordan and their colleagues at University College Nottingham in 1947 8 9 10 However the discovery of the DNA double helix also used a considerable amount of material from the unpublished work of Rosalind Franklin A R Stokes Maurice Wilkins and H R Wilson at King s College London Key data from Wilkins Stokes and Wilson and separately by Franklin and Gosling were published in two separate additional articles in the same issue of Nature with the article by Watson and Crick 11 12 The article by Watson and Crick acknowledged that they had been stimulated by experimental results from the King s College researchers and a similar acknowledgment was published by Wilkins Stokes and Wilson in the following three page article In 1968 Watson published a highly controversial autobiographical account of the discovery of the double helical molecular structure of DNA called The Double Helix which was not publicly accepted either by Crick or Wilkins 13 Furthermore Erwin Chargaff also printed a rather unsympathetic review of Watson s book in the 29 March 1968 issue of Science In the book Watson stated among other things that he and Crick had access to some of Franklin s data from a source that she was not aware of and also that he had seen without her permission the B DNA X ray diffraction pattern obtained by Franklin and Gosling in May 1952 at King s in London In particular in late 1952 Franklin had submitted a progress report to the Medical Research Council which was reviewed by Max Perutz then at the Cavendish Laboratory of the University of Cambridge Watson and Crick also worked in the MRC supported Cavendish Laboratory in Cambridge whereas Wilkins and Franklin were in the MRC supported laboratory at King s in London Such MRC reports were not usually widely circulated but Crick read a copy of Franklin s research summary in early 1953 13 14 Perutz s justification for passing Franklin s report about the crystallographic unit of the B DNA and A DNA structures to both Crick and Watson was that the report contained information which Watson had heard before in November 1951 when Franklin talked about her unpublished results with Raymond Gosling during a meeting arranged by M H F Wilkins at King s College following a request from Crick and Watson 15 Perutz said he had not acted unethically because the report had been part of an effort to promote wider contact between different MRC research groups and was not confidential 16 This justification would exclude Crick who was not present at the November 1951 meeting yet Perutz also gave him access to Franklin s MRC report data Crick and Watson then sought permission from Cavendish Laboratory head William Lawrence Bragg to publish their double helix molecular model of DNA based on data from Franklin and Wilkins By November 1951 Watson had acquired little training in X ray crystallography by his own admission and thus had not fully understood what Franklin was saying about the structural symmetry of the DNA molecule 14 Crick however knowing the Fourier transforms of Bessel functions that represent the X ray diffraction patterns of helical structures of atoms correctly interpreted further one of Franklin s experimental findings as indicating that DNA was most likely to be a double helix with the two polynucleotide chains running in opposite directions Crick was thus in a unique position to make this interpretation because he had formerly worked on the X ray diffraction data for other large molecules that had helical symmetry similar to that of DNA Franklin on the other hand rejected the first molecular model building approach proposed by Crick and Watson the first DNA model which in 1952 Watson presented to her and to Wilkins in London had an obviously incorrect structure with hydrated charged groups on the inside of the model rather than on the outside Watson explicitly admitted this in his book The Double Helix 14 See also editComparison of nucleic acid simulation software nucleic acid modeling Crystallography Miles from Tomorrowland a TV series 2015 2018 with twin admirals named Watson and Crick Paracrystallinity X ray scattering Keto enol tautomerism DNA the final key insight from a Pauling collaborator that the textbooks of the time were wrong that led to the solved structure Avery MacLeod McCarty experiment the first demonstration that DNA was likely to be the genetic material Chargaff s rules which showed that A T and G C occurred in equal amountsReferences edit Watson JD Crick FH April 1953 Molecular structure of nucleic acids a structure for deoxyribose nucleic acid Nature 171 4356 737 738 Bibcode 1953Natur 171 737W doi 10 1038 171737a0 PMID 13054692 S2CID 4253007 Cochran W Crick FHC and Vand V 1952 The Structure of Synthetic Polypeptides I The Transform of Atoms on a Helix Acta Crystallogr 5 581 586 Pauling L Corey RB 1953 A Proposed Structure for the Nucleic Acids PNAS 39 2 84 97 Bibcode 1953PNAS 39 84P doi 10 1073 pnas 39 2 84 PMC 1063734 PMID 16578429 Judson Horace Freeland 1979 Eighth Day of Creation Makers of the Revolution in Biology New York Simon amp Schuster ISBN 9780671254100 Discover the rules of DNA base pairing with an online simulator Perutz MF Randall JT Thomson L Wilkins MH Watson JD June 1969 DNA helix Science 164 3887 1537 9 Bibcode 1969Sci 164 1537W doi 10 1126 science 164 3887 1537 PMID 5796048 History Historic Figures Watson and Crick 1928 BBC Retrieved 15 June 2014 JM Gulland DO Jordan HF Taylor 1947 Deoxypentose nucleic acids Part II electrometric titration of the acidic and the basic groups of the deoxypentose nucleic acid of calf thymus J Chem Soc 1947 25 1131 41 Creeth J M Gulland J M and Jordan D O 1947 Deoxypentose nucleic acids Part III Viscosity and streaming birefringence of solutions of the sodium salt of the deoxypentose nucleic acid of calf thymus J Chem Soc 1947 25 1141 1145 Watson James D 2012 The Annotated and Illustrated Double Helix Ed Gann amp Witkowski Simon amp Schuster New York pp196 7 Franklin R Gosling RG 25 April 1953 Molecular configuration in sodium thymonucleate PDF Nature 171 4356 740 741 Bibcode 1953Natur 171 740F doi 10 1038 171740a0 PMID 13054694 S2CID 4268222 Wilkins MH Stokes AR Wilson HR 25 April 1953 Molecular structure of deoxypentose nucleic acids PDF Nature 171 4356 738 740 Bibcode 1953Natur 171 738W doi 10 1038 171738a0 PMID 13054693 S2CID 4280080 a b Beckwith Jon 2003 Double Take on the Double Helix In Victor K McElheny ed Watson and DNA Making a Scientific Revolution Cambridge MA Perseus Publishing p 363 ISBN 978 0 738 20341 6 OCLC 51440191 a b c Watson James D 1980 The Double Helix A Personal Account of the Discovery of the Structure of DNA Atheneum ISBN 978 0 689 70602 8 first published in 1968 Sayre Anne 1975 Rosalind Franklin and DNA New York Norton Perutz MF Randall JT Thomson L Wilkins MH Watson JD 27 June 1969 DNA helix Science 164 3887 1537 1539 Bibcode 1969Sci 164 1537W doi 10 1126 science 164 3887 1537 PMID 5796048 Bibliography editJudson Horace Freeland 1979 The Eighth Day of Creation Makers of the Revolution in Biology Simon and Schuster ISBN 978 0 671 22540 7 Maddox Brenda 2002 Rosalind Franklin The Dark Lady of DNA Harper Collins ISBN 978 0 060 98508 0 Olby Robert 1974 The Path to The Double Helix Discovery of DNA MacMillan ISBN 978 0 486 68117 7 with foreword by Francis Crick revised in 1994 with a 9 page postscript Watson James D 1980 The Double Helix A Personal Account of the Discovery of the Structure of DNA Atheneum ISBN 978 0 689 70602 8 first published in 1968 Wilkins Maurice 2003 The Third Man of the Double Helix The Autobiography of Maurice Wilkins Oxford University Press ISBN 978 0 198 60665 9 Life Story TV film a BBC dramatization about the scientific race to discover the DNA double helix External links edit nbsp Scholia has a work profile for Molecular Structure of Nucleic Acids A Structure for Deoxyribose Nucleic Acid Annotated copy of the article from San Francisco s Exploratorium Access Excellence Classic Collection article on DNA structure Linus Pauling and the Race for DNA A Documentary History Online versions edit Online version Original text at nature com National Library of Medicine s PDF copy in the Francis Crick Documents Collection Commemorative HTML version Am J Psychiatry 160 623 624 April 2003 Retrieved from https en wikipedia org w index php title Molecular Structure of Nucleic Acids A Structure for Deoxyribose Nucleic Acid amp oldid 1219398084, wikipedia, wiki, book, books, library,

article

, read, download, free, free download, mp3, video, mp4, 3gp, jpg, jpeg, gif, png, picture, music, song, movie, book, game, games.