Characterization of cytochromes from Methanosarcina strain Göl and their involvement in electron transport during growth on methanol.
AUTOR(ES)
Kamlage, B
RESUMO
Methanosarcina strain Gö1 was tested for the presence of cytochromes. Low-temperature spectroscopy, hemochrome derivative spectroscopy, and redox titration revealed the presence of two b-type (b559 and b564) and two c-type (c547 and c552) cytochromes in membranes from Methanosarcina strain Gö1. The midpoint potentials determined were Em,7 = -135 +/- 5 and -240 +/- 11 mV (b-type cytochromes) and Em,7 = -140 +/- 10 and -230 +/- 10 mV (c-type cytochromes). The protoheme IX and the heme c contents were 0.21 to 0.24 and 0.09 to 0.28 mumol/g of membrane protein, respectively. No cytochromes were detectable in the cytoplasmic fraction. Of various electron donors and acceptors tested, only the reduced form of coenzyme F420 (coenzyme F420H2) and the heterodisulfide of coenzyme M and 7-mercaptoheptanoylthreonine phosphate (CoM-S-S-HTP) were capable of reducing and oxidizing the cytochromes at a high rate, respectively. Addition of CoM-S-S-HTP to reduced cytochromes and subsequent low-temperature spectroscopy revealed the oxidation of cytochrome b564. On the basis of these results, we suggest that one or several cytochromes participate in the coenzyme F420H2-dependent reduction of the heterodisulfide.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=206100Documentos Relacionados
- Growth and Methanogenesis by Methanosarcina Strain 227 on Acetate and Methanol
- Growth substrate effects on acetate and methanol catabolism in Methanosarcina sp. strain TM-1.
- Development of Microbodies in the yeast Kloeckera growing on methanol.
- Electron Transport and Cytochromes of Sub-Cellular Particles from Cauliflower Buds. 1
- Coenzyme M derivatives and their effects on methane formation from carbon dioxide and methanol by cell extracts of Methanosarcina barkeri.
