Surín S, Cubonová L, Majerník AI, Smigán P. Amiloride resistance in the methanoarcheon Methanothermobacter thermoautotrophicus: characterization of membrane-associated proteins.
Folia Microbiol (Praha) 2006;
51:313-6. [PMID:
17007434 DOI:
10.1007/bf02931822]
[Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
An amiloride-resistant mutant with diminished Na+/H+ antiporter activity was isolated from Methanothermobacter thermoautotrophicus. To define the protein basis of amiloride resistance, the composition of membrane-associated proteins was partially characterized and compared with that of the wild type strain. An abundant 670-kDa membrane-associated protein that was present only in the mutant strain was analyzed by MALDI-TOF MS and identified as a coenzyme F420-reducing hydrogenase. The amiloride resistance was not accompanied by changes in protein size or changes in the level of subunits A or B of the A1A0-type ATP synthase; on the other hand, the SDS-PAGE patterns of the chloroform-methanol extract of membranes from both strains were different. Two bands with calculated molecular mass 16 and 11 kDa were identified as MtrD and AtpK, respectively. The observed over-expression of a 22.7-kDa protein in the mutant cells may represent the multimeric form of the MtrD subunit. These results show that the impairment of the Na+/H+ antiporter system in the amiloride-resistant mutant of Methanothermobacter thermoautotrophicus is accompanied by only small changes in a few membrane-associated proteins.
Collapse