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Title:Biochemical and chemical studies of the components involved in the final step of methane formation in Methanobacterium
Author(s):Olson, Karl Daniel
Doctoral Committee Chair(s):Wolfe, R.S.
Department / Program:Microbiology
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):Biology, Microbiology
Chemistry, Biochemistry
Abstract:The final step of methane formation in Methanobacterium thermoautotrophicum is a reductive demethylation of 2-(methylthio)ethanesulfonic acid (CH$\sb3$-S-CoM) with reducing equivalents from 7-(mercaptoheptanoyl)-L-threonine O$\sp3$-phosphate (HS-HTP). The enzyme that catalyzes this step is the CH$\sb3$-S-CoM reductase. Bound to the enzyme (non-covalently) is the prosthetic group, native coenzyme F430, a unique nickel-containing tetrapyrrole.
Coenzyme F430 and a structural analogue were purified to homogeneity and studied by several types of two-dimensional (2D) nuclear magnetic resonance (NMR) techniques. Modelling studies using 2D nuclear Overhauser effect spectroscopy (NOESY) data, and distance geometry (DG) and back-calculations were used to determine 3-D structural aspects of these molecules.
It was also found that inactive CH$\sb3$-S-CoM reductase can be partially activated in the presence of light. This is a major simplification of the terminal step. Interestingly, methanogens were found to be sensitive to visible light (in blue end of the spectrum).
Experiments were completed to determine the experimental mid-point potentials electrochemically. These experiments are described.
Issue Date:1991
Rights Information:Copyright 1991 Olson, Karl Daniel
Date Available in IDEALS:2011-05-07
Identifier in Online Catalog:AAI9210943
OCLC Identifier:(UMI)AAI9210943

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