Poly-beta-hydroxybutyrate/calcium polyphosphate complexes in eukaryotic membranes.
Poly-beta-hydroxybutyrate/calcium polyphosphate (PHB-CaPolyPi) complexes exist as labile quasi-crystalline structures in bacterial plasma membranes. The composition, structure, and distribution of the complex suggest it may play a role in the regulation of intracellular calcium and in calcium signaling. The importance of these functions led to this investigation of the occurrence of PHB-CaPolyPi complexes in eukaryotes. A variety of plant and animal systems were analyzed and all were found to contain PHB associated with CaPolyPi. The intracellular location of the complex in bovine liver was primarily the mitochondria and microsomes, with smaller amounts in the plasma membranes. Eukaryotic PHB had the same narrow range of chain lengths (120-200 subunits) as PHB in bacterial membranes, and was associated with PolyPi of somewhat greater length (170-220) than the bacterial counterpart (130-170).
Department of Microbiology and Public Health, Michigan State University, East Lansing.
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Reusch
D000818:Animals; D002130:Calcium Phosphates / Q000378:metabolism*; D002417:Cattle; D002462:Cell Membrane / Q000378:metabolism*; D006885:Hydroxybutyrates / Q000378:metabolism*; D007425:Intracellular Membranes / Q000378:metabolism; D007668:Kidney / Q000378:metabolism; D008099:Liver / Q000378:metabolism / Q000648:ultrastructure; D009682:Magnetic Resonance Spectroscopy; D010944:Plants; D011091:Polyesters / Q000378:metabolism*; D013347:Subcellular Fractions / Q000378:metabolism; D000094122:Polyhydroxybutyrates
D002130:Calcium Phosphates; D006885:Hydroxybutyrates; D011091:Polyesters; C003182:poly-beta-hydroxybutyrate; D000094122:Polyhydroxybutyrates