by James D. Watson I was much pleased when Watson asked me to write . curiosity about how the double helix was found, and to them an incomplete. The annotated and illustrated double helix / James D. Watson ; edited by Alexander of Watson, Crick, and Wilkins, but of Franklin, Linus Pauling, and others as. (The Double Helix Revisited. -Francis Crick and James Watson talk to Paul Vaughan about their discovery of the molecular structure of DNA. "VAUGHAN: James.
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About Books [PDF] The Double Helix: A Personal Account of the Discovery of the Structure of DNA by James D. Watson BEST BOOKS: The. The double helix: a personal account of the discovery of the structure of DNA by James D. Watson; 1 edition; First published in ; Subjects: Accessible book. PDF | On Apr 1, , Jonathan Wayne Riddle and others published A Book Report on The Double Helix () by James Watson.
I can deal here only briefly with them. I start with the problem of the replication of DNA. The principle of semi-conservative replication suggested itself to Crick and Watson directly from the structure of the double helix and is startlingly simple. But how does the helix actually unwind, and how does the sequence of each strand get copied?
The implementation is startingly complex. Nucleic acids are only synthesized in one direction 50 to 30 : how then does the antiparallel strand get copied? Again, the work of a generation of biochemists, notably Arthur Kornberg, has shown that it takes dozens of protein complexes, each involving many proteins to accomplish this. They can be thought of as complex components of several giant molecular machines Figure 33 , which synthesize the new DNA, check it for errors, and pass it on for further interactions which package it in chromosomes.
There was a second major question. How does the information carried by the sequence of bases in a DNA molecule get finally transferred into the sequence of amino acids in a protein? The central dogma was formulated by Watson as DNA makes RNA makes protein, and by Crick as sequence information can only pass from nucleic acid to protein and not in reverse.
This required the genetic code to be worked out Figure 34 which was largely accomplished by It has further taken a generation of biochemists to work out the actual biochemical mechanisms involved in transcribing DNA into RNA. The enzyme responsible is RNA Polymerase, of which there are three varieties in eurkaryotes. The enzyme is another complex molecular machine whose structure has recently been solved by Roger Kornberg Kornberg fils Figures 35 and 36 , and this enzyme acts only after a preinitiation complex, involving dozens of other proteins, has been set up to recruit it to the gene to be transcribed.
The product RNA is then processed and passed as a messenger from the cell nucleus to the cytoplasm to ribosomes, the protein factories which synthesize proteins of defined sequence. Here the message contained in the sequence of the nucleic acid is translated into a sequence of amino acids according to the genetic code Figure 34 , and also the polypeptide chain is assembled Figure Epilogue The discovery of the double helix and the elucidation of the genetic code launched the new subjects of molecular genetics and, combined with biochemistry, the molecular biology of the gene.
There also followed over the 50 years what has been called the genetic revolution in biotechnology but this did not stem directly from the new knowledge.
Rather it depended on the development of tools for handling and manipulating DNA. Segments of DNA could be cloned and multiplied in bacteria, and also used to express gene products in them. To these must be added many other powerful methods, for example, the introduction of site specific mutations in DNA, and the polymerase chain reaction which has replaced cloning for many purposes. Then there have also been great advances in understanding the regulation of gene expression, that is, the switching of genes on and off in the right place at the right time by combinations of protein transcription factors, interacting with the control regions of the gene.
In higher organisms the substrate, so to speak, for the expression is not naked DNA, but chromatin in which DNA is packaged in nucleosomes, so there are complex mechanisms for making the control regions accessible to the transcription machinery. Moreover since transcription factors working on a gene are themselves the products of other genes, we really need to understand the networking of genes. This takes us on to the genome, to the human genome project and to the comparative genomes of other organisms.
There is much more to find out. This paper is based on my lecture in Cambridge on 25 April during the 50th Anniversary celebrations of the Double Helix.
That lecture was an expanded version of an earlier one I gave in January at Darwin College, Cambridge. I thank Richard Henderson for useful comments on both. The newly transcribed RNA red will exit from the top left-hand corner Gnatt et al. Science, , ; courtesy of Roger Kornberg.
The two subunits of the ribosome. The 30 S subunit with the aid of tRNA, translates the sequence of the messenger RNA into a sequence of amino acids, which are successively assembled into a polypeptide chain.
The two subunits are linked physically and functionally by transfer RNA which, with one end, reads the genetic code on the 30 S subunit, and, at its other end, provides an activated amino acid for peptide synthesis on the 50 S subunit.
Courtesy D. Brodersen and V. Ramakrishnan, MRC, Cambridge. From original diagrams: 30 S: Wimberly, B. Structure of the 30 S ribosomal subunit. Nature , The complete atomic structure of the resolution.
Science , Watson, J. A structure for deoxyribose nucleic acid. Nature, , April 25, Wilkins, M. Molecular structure of deoxypentose nucleic acids. Franklin, R. Molecular configuration in sodium thymonucleate. Genetical implications of the structure of deoxyribonucleic acid.
Nature May 30, Crick, F. The complementary structure of deoxyribonucleic acid. Other Relevant Papers in Historical Order 6.
The structure of DNA. Cold Spring Harbor Symp. The structure of sodium thymonucleate fibres. The influence of water content. Acta Crystallog. Submitted March 6.
Evidence for 2-chain helix in crystalline structure of sodium deoxy-ribonucleate. Nature, , July 25, Helical structure of crystalline deoxypentose nucleic acid.
Nature, , October 24, Gosling, R. Thesis, University of London Langridge, R. The molecular configuration of deoxyribonucleic acid: X-ray diffraction analysis. The molecular configuration of deoxyribonucleic acid: molecular models and their Fourier transforms.
Other historical references Klug, A. Nature, , Perutz, M. Science, , Wilson, H. Trends Biochem. The Double Helix.
So, the autumn of , he went to Cambridge University and joined the group working in the Cavendish Laboratory.
Officially — to work on three-dimensional structures of proteins. Unofficially — to make a discovery which will grant him a Nobel. You think he may have overreacted? Himself included. Anyway, Watson and Crick may have had dreams of greatness, but neither of them had any clue how they were supposed to be the first to discover the structure of DNA when everybody who meant something in the world of biochemistry at the day was trying to achieve the same thing.
To put it mildly, the odds were against them. In London, Wilkins was working with Rosalind Franklin, gathering and analyzing data. But, you know how it goes: scarcity breeds invention — especially after hours.
And, as Machiavelli once said , the end justifies the means. Now, Watson and Crick were on to something. And everybody was aware that they were. Watson and Crick were stars. Unfortunately, four years before that, Rosalind Franklin succumbed to the ovarian cancer she was suffering from, at the very early age of But, not few are in it for the money or the fame.
And some — maybe even the majority of them — are in it because of all of that. They did a great deal to liven up the atmosphere of the lab, where experiments usually lasted several months to years. This came partly from the volume of Crick's voice: he talked louder and faster than anyone else and, when he laughed, his location within the Cavendish was obvious. Almost everyone enjoyed these manic moments, especially when we had the time to listen attentively and to tell him bluntly when we lost the train of his argument.
But there was one notable exception. Conversations with Crick frequently upset Sir Lawrence Bragg, and the sound of his voice was often sufficient to make Bragg move to a safer room. Only infrequently would he come to tea in the Cavendish, since it meant enduring Crick's booming over the tea room.
Even then Bragg was not completely safe. On two occasions the corridor outside his office was flooded with water pouring out of a laboratory in which Crick was working.
Francis, with his interest in theory, had neglected to fasten securely the rubber tubing around his suction pump. At the time of my arrival, Francis' theories spread far beyond the confines of protein crystallography.
Anything important would attract him, and he frequently visited other labs to see which new experiments had been done. Though he was generally polite and considerate of colleagues who did not realize the real meaning of their latest experiments, he would never hide this fact from them.
Almost immediately he would suggest a rash of new experiments that should confirm his interpretation. Moreover, he could not refrain from subsequently telling all who would listen how his clever new idea might set science ahead.