Studies on the Methylcoenzyme M Methylreductase System of Methanobacterium Thermoautotrophicum

The methylcoenzyme M methylreductase system of Methanobacterium thermoautotrophicum catalyzes the reductive demethylation of methylcoenzyme M by H$\sb2$. It had been previously shown to consist of four protein fractions, named components A1, A2, A3, and C. In this work, component A2 was purified to homogeneity using ATP-agarose affinity chromatography. This suggested that component A2 was involved in the activation of the system by ATP. The utilization of the dialdehyde of ATP showed that component A3 was also involved in this activation. When various sources of electrons were used, it was shown that the methylreductase system had two separate requirements for reducing equivalents, one of them to reactivate the methylreductase and the other to reduce methylcoenzyme M. Component A3 was then resolved in two fractions. One of them, called A4, contained one of the hydrogenases of Methanobacterium. The other, called component A3 per se, consisted of an FeS protein with a molecular weight of 500,000. A model for the functioning of the methylcoenzyme M methylreductase system, including components A1, A2, A3, A4, and C, as well as the dual requirement for reducing equivalents, was presented.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Microbiology

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2014

Author dc:creator

• Rouviere, Pierre Eugene

Contributors dc:contributor

• Wolfe, R.S.

• Biology, Microbiology

Identifier

(UMI)AAI8908818

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/71195