First among Equals — Francis Crick
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《新英格兰医药杂志》
Francis Crick, who died on July 28, was the premier theorist of molecular biology. Among the founders of the science, he stood out, first among equals — and few equals, at that: Max Delbrück, Linus Pauling, Jacques Monod, Max Perutz, all dead, and Fran?ois Jacob, Joshua Lederberg, James Watson, and Sydney Brenner. Though different in their approaches, these scientists shared a style of mind that Crick personified: they were relentless, committed, immersed. In the joy of battle, they could be brutally candid. A younger scientist who had worked with Crick once remarked that "Francis was ruthless, chopping up problems and solving them."
(Figure)
Dr. Francis Crick, 1979.
Photograph by Arnold Newman, Getty Images.
In February 1953, when they discovered the structure of DNA, Crick and Watson knew (thanks in part to Rosalind Franklin's x-ray crystallography) that it consisted of two chains of nucleotides, with backbones on the outside, held together by four kinds of bases protruding from the nucleotides. Crick established that the chains are antiparallel — running in opposite directions. He had learned from the work of Pauling the power of model building: a model demonstrates a theory. It was Watson who took the final and most original step, seeing that the unique pairing of the bases adenine and thymine is congruent with the pair cytosine and guanine, which tie the chains together with hydrogen bonds.
The structure is a thing of transcendent beauty and explanatory power. Perfectly parsimonious, it shows at a glance how genes replicate, passing down the generations, and how they are expressed, dictating the construction of proteins.
The biosynthesis of proteins was the next question — narrowly stated, this was the coding problem. In a review published in 1958, Crick advanced "the adaptor hypothesis." He postulated that the cell necessarily contains small molecules whose function is to bring the correct amino acids to the next positions in the growing protein chain. Calling for a new entity happens in physics but rarely in biology; adaptor molecules rank with William Harvey's postulation of anastomoses, unseen connections between the arterial and the venous networks so that the blood can circulate. The adaptors were soon found: they are transfer RNAs.
It was in that paper, too, that Crick propounded the central dogma of molecular biology: "Once `information' has passed into protein it cannot get out again." The central dogma is of the profoundest import, for it illuminates the physiological necessity for the rejection of Lamarckism, the inheritance of acquired traits.
At a meeting in Sydney Brenner's rooms in King's College, Cambridge, in the spring of 1960, Crick, Brenner, and Jacob came to the realization that genetic information is carried from DNA to the growing protein chain by an unstable RNA intermediate. In June of that year, Brenner and Jacob, with the help of Matthew Meselson, discovered the intermediate, soon called messenger RNA.
The Nobel Prize in Physiology or Medicine came in 1962, to Crick along with Watson. (Franklin had died; the third scientist included was Maurice Wilkins, who had worked for seven years refining the crystallographic data.)
In 1976, Crick moved from Cambridge to La Jolla, California, and the Salk Institute and switched fields. In the late 1940s, before going into molecular biology, he had considered neurobiology. A committed atheist, he wanted to undertake research that, aside from its intrinsic importance, could dispel the last vestiges of vitalism. Now he took up specifically the neurologic and cellular basis of consciousness, first mastering the literature and then, with such colleagues as Christof Koch at the California Institute of Technology, advancing a succession of ideas. He knew that he had not gone very far, but the effectiveness of his work went beyond the specifics. A neurobiologist told me, "Francis brought the problem of consciousness out of the closet, made it respectable. If Crick found it important, we'd better pay attention."
People who knew Crick only slightly often thought him cold. Yet he had passions and, above all, a passion for clarity. And if you came to Crick with a problem and he valued you, you didn't get sympathy. You got help. In some instances, Crick's help transformed lives.
Source Information
From Baltimore.(Horace Freeland Judson)
(Figure)
Dr. Francis Crick, 1979.
Photograph by Arnold Newman, Getty Images.
In February 1953, when they discovered the structure of DNA, Crick and Watson knew (thanks in part to Rosalind Franklin's x-ray crystallography) that it consisted of two chains of nucleotides, with backbones on the outside, held together by four kinds of bases protruding from the nucleotides. Crick established that the chains are antiparallel — running in opposite directions. He had learned from the work of Pauling the power of model building: a model demonstrates a theory. It was Watson who took the final and most original step, seeing that the unique pairing of the bases adenine and thymine is congruent with the pair cytosine and guanine, which tie the chains together with hydrogen bonds.
The structure is a thing of transcendent beauty and explanatory power. Perfectly parsimonious, it shows at a glance how genes replicate, passing down the generations, and how they are expressed, dictating the construction of proteins.
The biosynthesis of proteins was the next question — narrowly stated, this was the coding problem. In a review published in 1958, Crick advanced "the adaptor hypothesis." He postulated that the cell necessarily contains small molecules whose function is to bring the correct amino acids to the next positions in the growing protein chain. Calling for a new entity happens in physics but rarely in biology; adaptor molecules rank with William Harvey's postulation of anastomoses, unseen connections between the arterial and the venous networks so that the blood can circulate. The adaptors were soon found: they are transfer RNAs.
It was in that paper, too, that Crick propounded the central dogma of molecular biology: "Once `information' has passed into protein it cannot get out again." The central dogma is of the profoundest import, for it illuminates the physiological necessity for the rejection of Lamarckism, the inheritance of acquired traits.
At a meeting in Sydney Brenner's rooms in King's College, Cambridge, in the spring of 1960, Crick, Brenner, and Jacob came to the realization that genetic information is carried from DNA to the growing protein chain by an unstable RNA intermediate. In June of that year, Brenner and Jacob, with the help of Matthew Meselson, discovered the intermediate, soon called messenger RNA.
The Nobel Prize in Physiology or Medicine came in 1962, to Crick along with Watson. (Franklin had died; the third scientist included was Maurice Wilkins, who had worked for seven years refining the crystallographic data.)
In 1976, Crick moved from Cambridge to La Jolla, California, and the Salk Institute and switched fields. In the late 1940s, before going into molecular biology, he had considered neurobiology. A committed atheist, he wanted to undertake research that, aside from its intrinsic importance, could dispel the last vestiges of vitalism. Now he took up specifically the neurologic and cellular basis of consciousness, first mastering the literature and then, with such colleagues as Christof Koch at the California Institute of Technology, advancing a succession of ideas. He knew that he had not gone very far, but the effectiveness of his work went beyond the specifics. A neurobiologist told me, "Francis brought the problem of consciousness out of the closet, made it respectable. If Crick found it important, we'd better pay attention."
People who knew Crick only slightly often thought him cold. Yet he had passions and, above all, a passion for clarity. And if you came to Crick with a problem and he valued you, you didn't get sympathy. You got help. In some instances, Crick's help transformed lives.
Source Information
From Baltimore.(Horace Freeland Judson)