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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|
|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.
|Rights Information:||Copyright 1991 Olson, Karl Daniel|
|Date Available in IDEALS:||2011-05-07|
|Identifier in Online Catalog:||AAI9210943|