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Counterion collapse and the effect of diamines on bacteriorhodopsin
Author(s) -
Marinetti Tim
Publication year - 1987
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(87)80775-5
Subject(s) - bacteriorhodopsin , counterion , proton , diamine , chemistry , proton transport , inorganic chemistry , chemical physics , ion , polymer chemistry , organic chemistry , physics , membrane , biochemistry , quantum mechanics
A recent report of electrical measurements on oriented bacteriorhodopsin in gels [(1986) FEBS Lett. 195, 164–168] concluded that low concentrations of diamines reversed the direction of the proton pump. Calculations are presented which show that in low diamine concentrations, charge displacements of the counterion atmosphere in the direction opposite to proton pumping are expected following H + ejection. It is also shown that the effect will be sharply reduced by raising the diamine concentration or by adding excess salt, as was observed. Hence it is not necessary to conclude that diamines reverse the direction of the proton pump itself.