F0 cysteine,bCys21, in the Escherichia coli ATP synthase is involved in regulation of potassium uptake and molecular hydrogen production in anaerobic conditions |
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| Authors: | Mnatsakanyan Nelli Bagramyan Karine Vassilian Anait Nakamoto Robert K Trchounian Armen |
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| Institution: | (1) Department of Biophysics, Yerevan State University, 1 Alex Manougian Street, 375049 Yerevan, Armenia;(2) Department of Biochemistry of the Biological Faculty, Yerevan State University, 1 Alex Manougian Street, 375049 Yerevan, Armenia;(3) Department of Ecology and Nature Protection of the Biological Faculty, Yerevan State University, 1 Alex Manougian Str., 375049 Yerevan, Armenia;(4) Department of Molecular Physiology and Biological Physics, Health Sciences Center, The University of Virginia, Charlottesville, VA 22908, USA |
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| Abstract: | The single cysteine in the b subunit of the membranous F0 sector and the 19 cysteines in extramembranous F1 sector of the Escherichia coli ATP synthase were replaced by alanine. When cells were grown under anaerobic conditions on glucose, the k
cat for ATP hydrolysis of membrane vesicles containing the bCys21Ala mutant enzyme, but not enzymes with other cysteine replacements, was lower, while ATP-driven H+ pumping was unchanged. However, the ATP-dependent increase in the number of accessible thiol groups in membrane vesicles was negated. Furthermore, K+ uptake and molecular hydrogen production by whole cells and protoplasts was greatly decreased. These results indicate a role for the F0 subunit bCys21 in the functionality of F0F1 and coupling to other membranous activities under fermentative conditions. |
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| Keywords: | Cysteine residues ATP synthase potassium uptake formate hydrogen lyase fermentation Escherichia coli |
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