Ribosyl geometry in the transition state of Streptococcus pneumoniae methylthioadenosine nucleosidase from the 3'-(2)H kinetic isotope effect.
Synthesis of [3'-2H]-labeled 5'-methylthioadenosine (MTA) derivatives permitted measurement of the [3'-2H] KIE of the reaction catalyzed by Streptococcus pneumoniae methylthioadenosine nucleosidase (spMTAN). The key [3'-2H] 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.
Luo
Minkui
M
Department of Biochemistry, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, New York 10461, USA.
Schramm
Vern L
VL
D007700:Kinetics; D008958:Models, Molecular; D011683:Purine-Nucleoside Phosphorylase / Q000737:chemistry* / Q000378:metabolism; D013296:Streptococcus pneumoniae / Q000201:enzymology*
D011683:Purine-Nucleoside Phosphorylase; C021784:5'-methylthioadenosine phosphorylase