title: Functionally diverging molecular quasi-species evolve by crossing two enzymes.
abstract: Molecular evolution is frequently portrayed by structural relationships, but delineation of separate functional species is more elusive. We have generated enzyme variants by stochastic recombinations of DNA encoding two homologous detoxication enzymes, human glutathione transferases M1-1 and M2-2, and explored their catalytic versatilities. Sampled mutants were screened for activities with eight alternative substrates, and the activity fingerprints were subjected to principal component analysis. This phenotype characterization clearly identified at least three distributions of substrate selectivity, where one was orthogonal to those of the parent-like distributions. This approach to evolutionary data mining serves to identify emerging molecular quasi-species and indicates potential trajectories available for further protein evolution.
authors.affiliation: Department of Biochemistry and Organic Chemistry, Uppsala University, Biomedical Center, Box 576, SE-751 23 Uppsala, Sweden. lars.emren@biokemi.uu.se
authors.forename: Lars O
authors.initials: LO
authors.lastname: Emrén
authors.forename: Sanela
authors.initials: S
authors.lastname: Kurtovic
authors.forename: Arna
authors.initials: A
authors.lastname: Runarsdottir
authors.forename: Anna-Karin
authors.initials: AK
authors.lastname: Larsson
authors.forename: Bengt
authors.initials: B
authors.lastname: Mannervik
mesh_terms: D019143:Evolution, Molecular; D014644:Genetic Variation / Q000235:genetics*; D005982:Glutathione Transferase / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D006801:Humans; D007527:Isoenzymes / Q000145:classification / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D015394:Molecular Structure; D050506:Mutant Chimeric Proteins / Q000145:classification / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D009154:Mutation / Q000235:genetics; D013379:Substrate Specificity
chemical_list: D007527:Isoenzymes; D050506:Mutant Chimeric Proteins; D005982:Glutathione Transferase