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Polyphosphate at the Streptomyces lividans cytoplasmic membrane is enhanced in the presence of the potassium channel KcsA
Author(s) -
HEGERMANN J.,
LÜNSDORF H.,
OVERBECK J.,
SCHREMPF H.
Publication year - 2008
Publication title -
journal of microscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.569
H-Index - 111
eISSN - 1365-2818
pISSN - 0022-2720
DOI - 10.1111/j.1365-2818.2007.01863.x
Subject(s) - kcsa potassium channel , cytoplasm , chemistry , biophysics , polyphosphate , mutant , membrane , biochemistry , crystallography , biology , ion channel , phosphate , gene , receptor
Summary The distribution of polyphosphate (polyP) within the cytoplasmic membrane of Streptomyces lividans hyphae or protoplasts has been determined at high spatial resolution by elemental mapping using energy‐filtered electron microscopy (EFTEM). The results revealed that polyP was best traceable after its interaction with lead ions followed by their precipitation as lead sulphide. Concomitant studies of the S.lividans wildtype (WT) strain and its co‐embedded mutant ΔK (lacking a functional kcs A gene) were conducted by labelling as the surface matrix of either one was labelled by cationic colloidal thorium dioxide. Within the WT strain, additional polyP was found to accumulate distinctly at the inner face of the cytoplasmic membrane. After removal of the cell wall (within protoplasts), the polyP‐derived lead‐sulphide (PbS) precipitate formed clusters of fibrillar material extending up to 50 nm into the cytoplasm. This feature was absent in the ΔK mutant strain. Together the results revealed that the presence of the KcsA channel and the structured polyP coincide.