Methanosarcina thermophila

Murakami E, U Deppenmeier, SW Ragsdale (2001) Characterization of the intramolecular electron transfer pathway from 2-hydroxyphenazine to the heterodisulfide reductase from Methanosarcina thermophila. J Biol Chem 276 2432-2439. 

Iverson, T. M., Alber, B. E., Kisker, C., Ferry, J. G., and Rees, D. C. (2000). A closer look at the active site of gamma-class carbonic anhydrases High-resolution crystallographic studies of the carbonic anhydrase from Methanosarcina thermophila. Biochemistry 39, 9222-9231. 

The reactions unique to the pathway for Methanosarcina thermophila are shown in Figure 11.2 and Table 11.3. In the pathway, the carbon-carbon bond of acetate is cleaved, followed by reduction of the methyl group to methane with electrons originating from oxidation of the carbonyl group to carbon dioxide thus the pathway is a true fermentation. 

Alber BE, Colangelo CM, Dong J, et al. 1999. Kinetic and spectroscopic characterization of the gamma carbonic anhydrase from the methanoarchaeon Methanosarcina thermophila. Biochemistry 38 13119-28. 

Ingram-Smith C, Barber RD, Ferry JG. 2000. The role of histidines in the acetate kinase from Methanosarcina thermophila. J Biol Chem 275 33765-70. 

Kisker C, Schindelin H, Alber BE, et al. 1996. A left-handed beta-heUx revealed by the crystal structure of a carbonic anhydrase from the archaeon Methanosarcina thermophila. EMBO J 15 2323-30. 

Murakami E, Ragsdale SW. 2000. Evidence for intersnbnnit communication during acetyl-CoA cleavage by the multienzyme CO dehydrogenase/acetyl-CoA synthase complex from Methanosarcina thermophila. Evidence that the beta subunit catalyzes C-C and C-S bond cleavage. J Biol Chem 275 4699-707. 

Tripp BC, Ferry JG. 2000. A structure-function study of a proton transport pathway in a novel gamma-class carbonic anhydrase from Methanosarcina thermophila. Biochemistry 39 9232 0. 

Structure of y-Class Carbonic Anhydrase of Methanosarcina thermophila (Cam) A. Proposed C02 Hydration Mechanism for y-Class Carbonic Anhydrase... 

Aceti, D.J. Ferry, J.G. Purification and characterization of acetate kinase from acetate-grown Methanosarcina thermophila. J. Biol. Chem., 249, 15444-15448 (1988)... 

Buss, K.A. Ingram-Smith, C. Ferry, J.G. Sanders, D.A. Hasson, M.S. Crystallization of acetate kinase from Methanosarcina thermophila and prediction of its fold. Protein Sci., 6, 2659-2662 (1997)... 

Methanopterin (20) is a folate analogue that is isolated from an archae-bacteria, Methanosarcina thermophila, and the bacteria produces methane from CO2 under anaerobic conditions [18-24]. In the methane-producing metabolic process (Scheme 2), tetrahydromethanopterin (21) is known to work as a cofactor for the reduction of the Ci unit. Here, 21 accepts a formyl group that originates from CO2 and transforms it into the formyl... 

Novak PJ, Daniels L, Parkin GF. Enhanced dechlorination of carbon tetrachloride and chloroform in the presence of elemental iron and Methanosarcina barkeri, Methanosarcina thermophila, or Methanosaeta concilia. Environ Sci Technol 1998 32 1438-1443. 

A structure-function study of a proton pathway in the y-class carbonic anhydrase from Methanosarcina thermophila was conducted in the work of Tripp and Ferry (2000). Four enzyme glutamate residues were characterized by site-directed mutagenesis. It was shown that Glu 84 and an active site residue, Glu 89, are important for CO2 hydration activity, while external loop residues, Glu 88 and Glu 89 are less important. Glu 84 can be substituted for other ionizable residues with similar pKa values and, therefore, participates in the enzyme catalysis not as a chemical reagent but as a proton shuttle. 

The y-class of CAs has one structural representative from Methanosarcina thermophila While it retains three His ligands as in the a-class, the spacing characteristics change (Table 1). The resulting frimeric enzyme forms a zinc site from the interface of its subunits (sgg 6.1.2 and Table 5). 

A third family, the -carbonic anhydrases, also has been identified, initially in the archaeon Methanosarcina thermophila. The crystal structure of this enzyme reveals three zinc sites extremely similar to those in the a-carbonic anhydrases. In this case, however, the three zinc sites lie at the interfaces between the three subunits of a trimeric enzyme (Figure 9.31). The very striking left-handed P-helix (a P strand twisted into a left-handed helix) structure present in this enzyme has also been found in enzymes that catalyze reactions unrelated to those of carbonic anhydrase. Thus, convergent evolution has generated carbonic anhydrases that rely on coordinated zinc ions at least three times. In each case, the catalytic activity appears to be associated with zinc-bound water molecules. 

Monomeric ferredoxins have been isolated and characterized from three methano-sarcinaceae [124-127] and one methanococcal species [128,129]. The methanosarcinal ferredoxins have primary sequences similar to clostridial 2x[4Fe-4S] ferredoxins but differ in the configuration of their [Fe-S] centers. Although the ferredoxins isolated from M. barkeri MS and M. barkeri Fusaro both have molecular masses of approximately 6 kDa they contain a [3Fe-3S] cluster and 2x[4Fe—4S] clusters, respectively. The ferredoxin from Methanosarcina thermophila has a molecular mass of only 4.9 kDa and contains either a [3Fe-3S] or a [4Fe-4S] center. These ferredoxins appear to be involved in electron transport from pyruvate dehydrogenase and from CODH [125,130]. A ferredoxin purified from Methanococcus thermolithotrophicus has 2x[4Fe—4S] centers, a molecular mass of 7.3 kDa and also appears to accept electrons from CODH [128,129]. 

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