title: Urzymology: experimental access to a key transition in the appearance of enzymes.
abstract: Urzymes are catalysts derived from invariant cores of protein superfamilies. Urzymes from both aminoacyl-tRNA synthetase classes possess sophisticated catalytic mechanisms: pre-steady state bursts, significant transition-state stabilization of both amino acid activation, and tRNA acylation. However, they have insufficient specificity to ensure a fully developed genetic code, suggesting that they participated in synthesizing statistical proteins. They represent a robust experimental platform from which to articulate and test hypotheses both about their own ancestors and about how they, in turn, evolved into modern enzymes. They help reshape numerous paradigms from the RNA World hypothesis to protein structure databases and allostery.
authors.affiliation: Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, North Carolina 27599-7260. Electronic address: carter@med.unc.edu.
authors.forename: Charles W
authors.initials: CW
authors.lastname: Carter
mesh_terms: D000494:Allosteric Regulation; D000604:Amino Acyl-tRNA Synthetases / Q000737:chemistry / Q000235:genetics*; D055162:Biocatalysis; D020134:Catalytic Domain; D003062:Codon; D019143:Evolution, Molecular; D010802:Phylogeny; D014176:Protein Biosynthesis; D040681:Structural Homology, Protein; D013379:Substrate Specificity
chemical_list: D003062:Codon; D000604:Amino Acyl-tRNA Synthetases
keywords: Aminoacyl tRNA Synthetase; Bioinformatics; Genetic Code; Precellular Evolution; Protein Engineering; Protein Evolution; Protein Synthesis