The masked cysteine residues in methylmalonyl-CoA mutase from Propionibacterium shermanii are essential for catalytic activity.
Two masked cysteine residues have been reported in methylmalonyl-CoA mutase from Propionibacterium shermanii, Cys-535 in the alpha-subunit and Cys-517 in the beta-subunit, which are revealed only after reduction of the denatured enzyme with dithiothreitol. It has been postulated that these residues are involved in disulphide linkages to unknown thiols of low M(r). These two masked cysteine residues have been changed to an alanine, individually. Both the mutants, C535alphaA and C517betaA, were inactive. This shows that both these residues are essential for catalytic activity.
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Department of Biochemistry and Cambridge Centre for Molecular Recognition, University of Cambridge, UK. ipsita@dbed.iitd.ernet.in
D000409:Alanine / Q000737:chemistry; D003001:Cloning, Molecular; D003545:Cysteine / Q000737:chemistry* / Q000378:metabolism; D004220:Disulfides / Q000737:chemistry / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000235:genetics; D008765:Methylmalonyl-CoA Mutase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D016297:Mutagenesis, Site-Directed; D011424:Propionibacterium / Q000201:enzymology*; D017510:Protein Folding; D011994:Recombinant Proteins; D013438:Sulfhydryl Compounds / Q000737:chemistry
D004220:Disulfides; D011994:Recombinant Proteins; D013438:Sulfhydryl Compounds; D008765:Methylmalonyl-CoA Mutase; D003545:Cysteine; D000409:Alanine