Open AccessIsolation and characterization of an amiloride‐resistant mutant of Methanothermobacter thermautotrophicus possessing a defective Na + /H + antiport
Author(s) -
Šurín Stanislav,
Čuboňová L'ubomíra,
Majerník Alan I.,
McDermott Paul,
Chong James P. J.,
Šmigáň Peter
Publication year - 2007
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.2007.00655.x
Subject(s) - amiloride , antiporter , mutant , methanogenesis , chemistry , efflux , biochemistry , sodium , wild type , sodium–hydrogen antiporter , ion transporter , biology , membrane , organic chemistry , methane , gene
A spontaneous mutant of Methanothermobacter thermautotrophicus resistant to the Na + /H + antiporter inhibitor amiloride was isolated. The Na + /H + exchanger activity in the mutant cells was remarkably decreased in comparison with wild‐type cells. Methanogenesis rates in the mutant strain were higher than wild‐type cells and resistant to the inhibitory effect of 2 mM amiloride. In contrast, methanogenesis in wild‐type cells was completely inhibited by the same amiloride concentration. ATP synthesis driven by methanogenic electron transport or by an electrogenic potassium efflux in the presence of sodium ions was significantly enhanced in the mutant cells. ATP synthesis driven by potassium diffusion potential was profoundly inhibited in wild‐type cells by the presence of uncoupler 3,3′,4′,5‐ tetrachlorosalicylanilide and sodium ions, whereas c . 50% inhibition was observed in the mutant cells under the same conditions.