title: Structural study of Carcinus maenas hemocyanin by native ESI-MS: interaction with L-lactate and divalent cations.
abstract: The interaction of L-lactate and divalent cations with Carcinus maenas hemocyanin has been probed by electrospray ionization mass spectrometry under conditions preserving noncovalent interactions (native ESI-MS). C. maenas native hemocyanin in the hemolymph occurs mainly as dodecamers and to a lesser extent as hexamers. A progressive acidification with formic acid after alkaline dissociation resulted in the preferential recruitment of the two lightest subunits into light dodecamers, a molecular complex absent from native hemolymph, in addition to regular dodecamers and hexamers. Addition of L-lactic acid also induced the recruitment of these subunits, even at alkaline pH. A dodecamer-specific subunit is needed to enable aggregation over the hexameric state. Experiments with EDTA suggested the existence of different binding sites and association constants for divalent cations within hexameric structures and at the interface between two hexamers. L-lactic acid specific interaction with the lightest subunits was not inhibited by removal of the divalent cations.
authors: UPMC Univ. Paris 06, UMR 7144, Equipe Ecophysiologie: Adaptation et Evolution MoleCculaires, Station Biologique de Roscoff, 29682 Roscoff, France.
authors: Matthieu
authors: M
authors: Bruneaux
authors: Peran
authors: P
authors: Terrier
authors: Emmanuelle
authors: E
authors: Leize
authors: Jean
authors: J
authors: Mary
authors: François H
authors: FH
authors: Lallier
authors: Franck
authors: F
authors: Zal
mesh_terms: D000494:Allosteric Regulation; D000818:Animals; D001665:Binding Sites; D003386:Brachyura / Q000378:metabolism*; D002412:Cations; D002614:Chelating Agents / Q000494:pharmacology; D004492:Edetic Acid / Q000737:chemistry; D005561:Formates / Q000737:chemistry; D006433:Hemocyanins / Q000737:chemistry*; D006458:Hemolymph / Q000378:metabolism; D019344:Lactic Acid / Q000737:chemistry*; D013058:Mass Spectrometry / Q000379:methods*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*
chemical_list: D002412:Cations; D002614:Chelating Agents; D005561:Formates; C030544:formic acid; D019344:Lactic Acid; D006433:Hemocyanins; D004492:Edetic Acid