Biochemistry of Methyl-Coenzyme M Reductase: The Nickel Metalloenzyme that Catalyzes the Final Step in Synthesis and the First Step in Anaerobic Oxidation of the Greenhouse Gas Methane - The Metal-Driven Biogeochemistry of Gaseous Compounds in the Environment - page 122

Chapter 6
Biochemistry of Methyl-Coenzyme M
Reductase: The Nickel Metalloenzyme
that Catalyzes the Final Step in Synthesis
and the First Step in Anaerobic Oxidation
of the Greenhouse Gas Methane

Stephen W. Ragsdale

Contents
ABSTRACT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126

1 INTRODUCTION ......................................................................... 126

1.1 Nickel Enzymes Involved in Metabolism of Environment-
and Energy-Relevant Gases ......................................................... 126

1.2 Methyl-Coenzyme M Reductase and Its Involvement
in Generation and Utilization of Methane .......................................... 127

1.3 Ramifications of Methanogenesis in Energy
and the Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128

1.4 Discoveries Underpinning Recent Studies
of Methyl-Coenzyme M Reductase ................................................. 128

2 STRUCTURE AND PROPERTIES OF METHYL-COENZYME M
REDUCTASE AND ITS BOUND COENZYME F 430 .................................. 129

2.1 Structure, Properties, and Reactivity of Coenzyme F 430 .......................... 129

2.2 Structure, Properties, and Reactivity
of Methyl-Coenzyme M Reductase ................................................. 130

3 REDOX AND COORDINATION PROPERTIES OF THE NICKEL CENTER
IN METHYL-COENZYME M REDUCTASE .......................................... 133

3.1 Coordination and Oxidation States of the Free F 430
Cofactor and Its Pentamethyl Ester Derivative . . . ................................. 133

3.2 Coordination and Oxidation States of the Nickel Center . . ........................ 134

4 THE CATALYTIC MECHANISM OF METHYL-COENZYME M REDUCTASE . . 137

5 SUMMARY AND PROSPECTS FOR FUTURE SCIENCE AND TECHNOLOGY . . 140

ABBREVIATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142

ACKNOWLEDGMENTS ..................................................................... 142

REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142