Structural Basis of the Hydride Transfer Mechanism in F420-Dependent Methylenetetrahydromethanopterin Dehydrogenase
- 29 September 2009
- journal article
- research article
- Published by American Chemical Society (ACS) in Biochemistry
- Vol. 48 (42), 10098-10105
- https://doi.org/10.1021/bi901104d
Abstract
F420-dependent methylenetetrahydromethanopterin (methylene-H4MPT) dehydrogenase (Mtd) of Methanopyrus kandleri is an enzyme of the methanogenic energy metabolism that catalyzes the reversible hydride transfer between methenyl-H4MPT+ and methylene-H4MPT using coenzyme F420 as hydride carrier. We determined the structures of the Mtd−methylene-H4MPT, Mtd−methenyl-H4MPT+, and the Mtd−methenyl-H4MPT+-F420H2 complexes at 2.1, 2.0, and 1.8 Å resolution, respectively. The pterin−imidazolidine−phenyl ring system is present in a new extended but not planar conformation which is virtually identical in methenyl-H4MPT+ and methylene-H4MPT at the current resolution. Both substrates methenyl-H4MPT+ and F420H2 bind in a face to face arrangement to an active site cleft, thereby ensuring a direct hydride transfer between their C14a and C5 atoms, respectively. The polypeptide scaffold does not reveal any significant conformational change upon binding of the bulky substrates but in turn changes the conformations of the substrate rings either to avoid clashes between certain ring atoms or to adjust the rings involved in hydride transfer for providing an optimal catalytic efficiency.This publication has 38 references indexed in Scilit:
- Catalytic Cycle of Human Glutathione Reductase Near 1 Å ResolutionJournal of Molecular Biology, 2008
- Phasercrystallographic softwareJournal of Applied Crystallography, 2007
- Coot: model-building tools for molecular graphicsActa Crystallographica Section D-Biological Crystallography, 2004
- Coenzyme Binding in F420-Dependent Secondary Alcohol Dehydrogenase, a Member of the Bacterial Luciferase FamilyStructure, 2004
- Coenzyme F420-dependent Methylenetetrahydromethanopterin Dehydrogenase (Mtd) from Methanopyrus kandleri: A Methanogenic Enzyme with an Unusual Quarternary StructureJournal of Molecular Biology, 2003
- Refinement of Macromolecular Structures by the Maximum-Likelihood MethodActa Crystallographica Section D-Biological Crystallography, 1997
- Protein Structure Comparison by Alignment of Distance MatricesJournal of Molecular Biology, 1993
- Main-chain Bond Lengths and Bond Angles in Protein StructuresJournal of Molecular Biology, 1993
- Substrate binding and catalysis by glutathione reductase as derived from refined enzyme: Substrate crystal structures at 2Å resolutionJournal of Molecular Biology, 1989
- Coenzyme F420 dependence of the methylenetetrahydromethanopterin dehydrogenase of MethanobacteriumthermoautotrophicumBiochemical and Biophysical Research Communications, 1985