Open AccessElectron‐Dense Granules in Desulfovibrio gigas do not Consist of Inorganic Triphosphate but of a Glucose Pentakis(Diphosphate)
Author(s) -
Hensgens Charles M. H.,
Santos Helena,
Zhang Chenghong,
Kruizinga Wim H.,
Hansen Theo A.
Publication year - 1996
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1996.0327r.x
Subject(s) - chemistry , polyphosphate , magnesium , biochemistry , nuclear magnetic resonance spectroscopy , desulfovibrio , nuclear chemistry , sulfate , crystallography , stereochemistry , phosphate , organic chemistry
Under certain growth conditions the sulfate‐reducing bacterium Desulfovibrio gigas forms electron‐dense granules in the cells which had been claimed to consist of a magnesium triphosphate). We observed granules after cultivation in media with a low Fe 2+ or NH + 4 concentration and reinvestigated the nature of the electron‐dense bodies. Energy‐dispersive X‐ray analysis of the granules in the cells showed that they contain large amounts of P, Mg, and K. Gel electrophoresis and chromatographic analyses of isolated granules which had been dissolved in 20 mM EDTA, however, revealed discrepancies with commercially available polyphosphates. 31 P‐NMR spectra also lacked the peaks in the −22‐ppm region which are characteristic for inner phosphates of polyphosphates confirming that the phosphocompound as isolated from the electron‐dense bodies of D. gigas did not consist of polyphosphates. Using multinuclear NMR spectroscopy we showed that the electron‐dense bodies of D. gigas contained a novel metabolite which was identified as α‐glucose 1,2,3,4,6‐pentakis(diphosphate).