title: Evolution of enzyme structure.
abstract: Three-dimensional structures of enzymes offer evidence about their evolution. There are clear examples of divergent families (e.g. mammalian serine proteases) and convergence (e.g. chymotrypsin and subtilisin). Topological similarities in dehydrogenases may reflect an ancient divergence or merely chemical constraints on protein architectures. Further experimental evidence is desirable to back up arguments based on molecular morphology. By growing microorganisms on novel foodstuffs in a chemostat, one can focus selective pressure on a specific enzyme activity. Experiments will be described in which such pressure is focused on pentitol metabolism. Examination of the fine structure of the genes responsible for this pentitol metabolism has given clues about the volution of metabolic pathways.
mesh_terms: D000595:Amino Acid Sequence; D005075:Biological Evolution; D055598:Chemical Phenomena; D002621:Chemistry; D004798:Enzymes / Q000502:physiology*; D004926:Escherichia coli / Q000235:genetics; D007711:Klebsiella pneumoniae / Q000235:genetics; D008967:Molecular Biology; D008968:Molecular Conformation; D009876:Operon; D010447:Peptide Hydrolases / Q000235:genetics; D012255:Ribitol / Q000235:genetics; D012694:Serine; D013045:Species Specificity; D013305:Streptomyces griseus / Q000235:genetics; D013402:Sugar Alcohols / Q000235:genetics
chemical_list: D004798:Enzymes; D013402:Sugar Alcohols; D012694:Serine; D012255:Ribitol; D010447:Peptide Hydrolases