Scholarly Research Excellence
%0 Journal Article
%A Keun Woo Lee and  Minky Son and  Chanin Park and  Ayoung Baek
%D 2013 
%J  International Journal of Biological, Biomolecular, Agricultural, Food and Biotechnological Engineering
%B World Academy of Science, Engineering and Technology
%I International Science Index 73, 2013
%T Molecular Mechanism of Amino Acid Discrimination for the Editing Reaction of E.coli Leucyl-tRNA Synthetase
%V 73
%X Certain tRNA synthetases have developed highly accurate molecular machinery to discriminate their cognate amino acids. Those aaRSs achieve their goal via editing reaction in the Connective Polypeptide 1 (CP1). Recently mutagenesis studies have revealed the critical importance of residues in the CP1 domain for editing activity and X-ray structures have shown binding mode of noncognate amino acids in the editing domain. To pursue molecular mechanism for amino acid discrimination, molecular modeling studies were performed. Our results suggest that aaRS bind the noncognate amino acid more tightly than the cognate one. Finally, by comparing binding conformations of the amino acids in three systems, the amino acid binding mode was elucidated and a discrimination mechanism proposed. The results strongly reveal that the conserved threonines are responsible for amino acid discrimination. This is achieved through side chain interactions between T252 and T247/T248 as well as between those threonines and the incoming amino acids.

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