Characterisation of a red form of methanol dehydrogenase from the marine methylotroph Methylophaga marina |
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Authors: | HTC Chan C Anthony |
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Institution: | SERC Centre for Molecular Recognition, Department of Biochemistry, University of Southampton, Southampton, UK |
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Abstract: | Abstract The quinoprotein methanol dehydrogenase (MDH) of the marine methylotroph Methylophaga marina is similar to that of other methylotrophs in being an α 2 β 2 tetramer containing two molecules of PQQ and a single atom of calcium. Its electron acceptor is cytochrome c L and interaction of the two proteins is by way of carboxylates on the cytochrome and lysyl residues on the α subunit of MDH. The reaction was not, however, sensitive to high ionic strength as was the reaction in non-halophilic bacteria. A red form of the enzyme was sometimes produced which had a low specific activity and a low calcium content. Activity was restored by incubation with Ca2+ which also produced the typical (green) enzyme, with a typical absorption spectrum. This provides the first demonstration of reconstitution of active MDH from enzyme lacking calcium isolated from a wild-type methylotroph. |
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Keywords: | Methylophaga marina Methanol dehydrogenase Quinoprotein PQQ Cytochrome cL Calcium |
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