This week is the international DNA week!
This year we celebrate the 60th anniversary of the discovery of the DNA double helix by Watson and Crick which was achieved with the help of X-ray diffraction data produced by Rosalind Franklin and Maurice Wilkins.
We also celebrate the invention of the PCR reaction 30 years ago by Kary Mullis.
And we celebrate the 10th anniversary of the completion of the Human Genome Project as well.
On April 25, 1953 J. D. Watson and F. H. C. Crick published in the Journal “Nature” a paper called
“MOLECULAR STRUCTURE OF NUCLEIC ACIDS
A Structure for Deoxyribose Nucleic Acid”.
This established “Molecular Biology” as a science !
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“avian influenza A(H7N9) virus.”
(Left) Proposed structure. (Second from the left) X-ray diffraction photograph and diffraction pattern (3rd from the left) from Wilkens, Stokes and Wilson. X-ray diagram of structure B from Franklin and Gosling (to the right).
The original papers were published on April 25, 1953
A Structure for Deoxyribose Nucleic Acid. Watson J.D. and Crick F.H.C. Nature 171, 737-738 (1953)
In this paper the double helical structure of DNA was first described. It was also noted that the structure “suggests a possible copying mechanism for the genetic material”.
Molecular Structure of Deoxypentose Nucleic Acids. Wilkins M.H.F., A.R. Stokes A.R. & Wilson, H.R. Nature 171, 738-740 (1953)
In the same issue the X-Ray crystallography evidence was analyzed by Wilkins, Stokes and Wilson. They suggest evidence that the structure exists in biological systems.
Molecular Configuration in Sodium Thymonucleate. Franklin R. and Gosling R.G. Nature 171, 740-741 (1953)
Rosalind Franklin and Ray Gosling provide further evidence of the helical nature of nucleic acids by publishing a very nice diffraction pattern of calf thymus sodium deoxyribose nucleate. Finely they concluded that the phosphate backbone lies on the outside of the structural unit.
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In a follow up paper published on May 30, 1953 Watson and Crick discuss more details of the structure:
Genetical Implications of the structure of Deoxyribonucleic Acid. Watson J.D. and Crick F.H.C. Nature 171, 964-967 (1953).
In this second paper Watson and Crick follow up with largely accurate speculation on how base pairing in the double helix allows replication of DNA.
Models of the DNA structure are shown. Figure 1, 2 and 3 are from the paper.
Figure 4 and 5 taken from the paper show the now famous “Watson & Crick Base Pairing” of the nucleotides.
Here the base pairs are formed by hydrogen bonds between adenine and thymine, and, guanine and cytosine.
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The papers can be down loaded from the following site “Nature achieves: double helix: 50 years of DNA“.
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The birth of the science of molecular biology is nicely described in the book reviewed in Nature by Vernon M. Ingram; The birth of molecular biology. Nature 419, 669-670 (17 October 2002) | doi:10.1038/419669a.
A selected paragraph from the cited paper is shown next:
“In the late 1940s and early 1950s, Perutz attracted a nucleus of remarkably able young collaborators. His single-minded devotion to the task and his personality were key to this collaboration coming together. There was John Kendrew, who solved the structure of the muscle protein myoglobin; Francis Crick and James Watson, who solved the structure of DNA; Tony Broad, the engineer who made the most powerful X-ray machine in the world; Hugh Huxley, who (with Jean Hanson) solved the molecular mechanism of muscle contraction; and, a little later, Sydney Brenner, who with Crick founded much of modern molecular genetics. I was fortunate to be an early member of the group (1952–58), working as a protein chemist, helping the X-ray crystallographers, and studying the defect caused by the sickle-cell-anaemia mutation. Perutz was mentor to the whole group.”
I recommend that you read Chadarevian’s historical account especially if you are interested in the development of molecular biology.
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Nowadays DNA polymers, RNA polymers, peptides and small proteins can be routinely synthesized, both, using established chemical and enzymatic biochemical methods.
Biosynthesis Inc. can help you with your synthesis needs.
Please contact us at: http://www.biosyn.com
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