Historical opinion: Erwin Chargaff and his 'rules' for the base composition of DNA: why did he fail to see the possibility of complementarity?

Erwin Chargaff was one of the more interesting and colourful figures of the historic decade that heralded the proposal of the double helical structure of DNA by Watson and Crick in 1953. In describing Chargaff's important contribution to the study of DNA, particularly its base composition, this article seeks to suggest why, despite his substantial achievements, he failed to anticipate some of the key features of the Watson-Crick model, particularly complementarity between bases--a failure that left him deeply embittered for the rest of his life.

The crystallization of enzymes and virus proteins: laying to rest the colloidal concept of living systems.

In 1946 three Americans shared the Nobel Prize for Chemistry--James Sumner 'for his discovery that enzymes can be crystallized', and John Northrop and Wendell Stanley 'for their preparation of enzymes and virus proteins in a pure form'. The award made history as the first time that the Chemistry Prize was shared by three individuals. It also doubled the number of Americans that had received the Chemistry award since its inception in 1901.

Determination of the kinetics of guanine nucleotide exchange on EF-Tu and EF-Ts: continuing uncertainties.

An analysis is made of the rate constants for the reactions involving the interactions of EF-Tu, EF-Ts, GDP, and GTP recently derived by Gromadski et al. [Biochemistry 41 (2002) 162]. Though their measured values appear to allow a reasonable rate of nucleotide exchange sufficient to support rates of protein synthesis in vivo, their data underestimate the thermodynamic barrier involved in nucleotide exchange and therefore cannot be considered definitive.

Optimization of protein therapeutics by directed evolution.

Directed evolution is a broadly applicable technology platform that is ideally suited to address the need for protein optimization and to fully exploit the therapeutic potential of biologics. The approach takes advantage of the remarkable structural and functional plasticity of proteins and permits the rapid remodeling of biologics into new entities with improved functions. The ability to ameliorate virtually any characteristic of a protein can translate into significant clinical benefits, including decreased immunogenicity, higher potency, greater efficacy and improved safety profile, and can considerably increase the probability of successfully developing and commercializing biotherapeutics.

Man of destiny: the life and work of Fritz Haber.

'The German physical chemist Fritz Haber was distinguished not only for his researches, but also for his services to industry and to his country. Haber and the research institutes he directed contributed to a wide range of advances in physical chemistry. His most outstanding scientific achievement was his synthesis of ammonia, which solved the urgent problem of meeting the world demand for nitrogen fertiliser'.