The complementarity principle and the origin of macromolecular information

Abstract

I am going to try to revitalize an old and controversial relationship which appears to have lost much of its significance and excite­ ment largely through a kind of superficial familiarity. This is the relation between bio­ logical information and biological structure. It is now common jargon even among the most reductionistic molecular biologists to speak of information in macromolecules, such as gene­ tic DNA, hormones or immunoglobulins, as if information were a physical property like their structure and chemistry. But, as Kendrew (1967) and Stent (1968) have so clearly recalled, the origin of molecular biology involved 2 disjoint and even hostile groups: the with an ancestry of experi­ mental X-ray crystallographers going back to Bemal, Astbury and the Braggs; and the informationists with an ancestry in phage genetics associated with Delbruck, but with strong hereditary influences from Schrodinger and Bohr. As Kendrew and Stent saw it over a decade ago, there existed 2 schools of molecular biologists, structurists and informationists, three-dimensionists, and one-dimensionists, whose conceptual foundations had little in common. The were largely moti­ vated by the power of their experimental technique, X-ray diffraction, to eventually determine the three-dimensional atomic stucture of proteins and nucleic acids, reflecting what Stent (1968) calls a down-to-earth view of the relation of physics to biology, namely that all biological phenomena, no matter what their complexity, can ultimately be accounted for in terms of conventional physical laws. By contrast, the information­ ists were largely motivated by theoretical doubts of the adequacy of physics to explain life, in any reductionistic or purely objective sense. These doubts were suggestively ex­ pressed by Bohr (1934) and Schrodinger (1945) who did not speak in informational jargon, since it did not exist at the time, but who were nevertheless both focusing on informational questions: Bohr on the pro­ blem of measurement and its possible inter­ ference with vital dynamics, and Schrodinger on the problem of explaining the incredible reliability of genetic instructions. There was,