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Mechanism of lipid‐body formation in prokaryotes: how bacteria fatten up
Author(s) -
Wältermann Marc,
Hinz Andreas,
Robenek Horst,
Troyer David,
Reichelt Rudolf,
Malkus Ursula,
Galla HansJoachim,
Kalscheuer Rainer,
Stöveken Tim,
Von Landenberg Philipp,
Steinbüchel Alexander
Publication year - 2005
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.2004.04441.x
Subject(s) - cytoplasm , biology , acinetobacter calcoaceticus , biochemistry , lipid droplet , lipid ii , bacteria , lipid metabolism , diacylglycerol kinase , organelle , lipid bilayer , vesicle , membrane lipids , acinetobacter , enzyme , microbiology and biotechnology , membrane , biosynthesis , antibiotics , genetics , protein kinase c
Summary Neutral lipid accumulation is frequently observed in some Gram‐negative prokaryotes like Acinetobacter sp. and most actinomycetes, including the pathogenic Mycobacterium tuberculosis and antibiotic producing streptomycetes. We examined the formation of wax ester‐ and triacylglycerol (TAG)‐bodies in Acinetobacter calcoaceticus and Rhodococcus opacus using microscopic, immunological and biophysical methods. A general model for prokaryotic lipid‐body formation is proposed, clearly differing from the current models for the formation of lipid inclusions in eukaryotes and of poly(hydroxyalkanoic acid) (PHA) inclusions in prokaryotes. Formation of lipid‐bodies starts with the docking of wax ester synthase/acyl‐CoA:diacylglycerol acyltransferase (WS/DGAT) to the cytoplasm membrane. Both, analyses of in vivo and in vitro lipid‐body synthesis, demonstrated the formation of small lipid droplets (SLDs), which remain bound to the membrane‐associated enzyme. SLDs conglomerated subsequently to membrane‐bound lipid‐prebodies which are then released into the cytoplasm. The formation of matured lipid‐bodies in the cytoplasm occurred by means of coalescence of SLDs inside the lipid prebodies, which are surrounded by a half‐unit membrane of phospholipids.