Ribosyl geometry in the transition state of Streptococcus pneumoniae methylthioadenosine nucleosidase from the 3 '-(2)H kinetic isotope effect

Department of Biochemistry, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, New York 10461, USA.
Journal of the American Chemical Society (Impact Factor: 11.44). 10/2008; 130(35):11617-9. DOI: 10.1021/ja804578m
Source: PubMed

ABSTRACT Synthesis of [3'-(2)H)-labeled 5'-methylthioadenosine (MTA) derivatives permitted measurement of the [3'-(2)H) KIE of the reaction catalyzed by Streptococcus pneumoniae methylthioadenosine nucleosidase (spMTAN). The key [3'-(2)H) KIE revealed the partial 3'-OH polarization and H3'-endo -> exo ribosyl configuration at the spMTAN transition state. A new understanding of the transition state stabilization of spMTAN-catalyzed hydrolysis is uncovered in structural features at the spMTAN transition state.

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