Detection, synthesis, structure, and function of oligo(3-hydroxyalkanoates): contributions by synthetic organic chemists.
Two types of the biological macromolecules poly(R-3-hydroxyalkanoates) have been identified: the high-molecular-weight microbial storage material (sPHA) and a short-chain variety, consisting of butyrate and valerate residues, complexed with other biomacromolecules such as calcium polyphosphate or proteins (cPHB/PHV). While sPHA has attracted, and still enjoys, a lot of attention from numerous scientists around the world, research on cPHB and the structurally and functionally related polymalate (PMA) is still in its infancy. In this article, we present a review on the chemical synthesis, structure, function and interactions of monodisperse cPHAs, the oligo(3-hydroxyalkanoates), with emphasis on the butyrates (OHB); we report hitherto unpublished results on the enzymatic degradation of cPHB and PMA, on a new analytical method for HB/HV detection in biological samples, and on OHB-mediated Ca2+ transport through phospholipid bilayers of artificial vesicles; finally, we discuss possible mechanisms of ion transport through cell membranes, as caused by cPHB. The speculative--and provocative--question is asked whether the structurally simple PHAs may have evolved as storage materials and amphiphilic macromolecules before poly-peptides, -saccharides, and -nucleic acids, in the history of life, or under prebiotic conditions.
Laboratorium für Organische Chemie der Eidgenossischen Technischen Hochschule Zürich, ETH-Zentrum, Switzerland. seebach@org.chem.ethz.ch
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D000818:Animals; D001673:Biodegradation, Environmental; D002130:Calcium Phosphates / Q000737:chemistry / Q000378:metabolism; D002265:Carboxylic Ester Hydrolases / Q000378:metabolism; D008958:Models, Molecular; D008968:Molecular Conformation; D015394:Molecular Structure; D009024:Morphogenesis / Q000187:drug effects; D011091:Polyesters / Q000737:chemistry* / Q000378:metabolism* / Q000633:toxicity; D013723:Teratogens / Q000633:toxicity
D002130:Calcium Phosphates; D011091:Polyesters; D013723:Teratogens; D002265:Carboxylic Ester Hydrolases; C022417:poly-beta-hydroxybutyrate depolymerase