title: Processing of Bacillus subtilis succinate dehydrogenase and cytochrome b-558 polypeptides. Lack of covalently bound flavin in the Bacillus enzyme expressed in Escherichia coli.
abstract: The DNA sequence of the Bacillus subtilis sdh operon coding for the two succinate dehydrogenase subunits and cytochrome b-558 (the membrane anchor protein) has recently been established. We have now determined the extent of N-terminal processing of each polypeptide by radiosequence analysis. At the same time, direct evidence for the correctness of the predicted reading frames has been obtained. The cytochrome showed a ragged N-terminus, with forms lacking one residue, and is inserted across the membrane without an N-terminal leader-peptide. Covalently bound flavin was not detectable in B. subtilis succinate dehydrogenase expressed in Escherichia coli despite normal N-terminal processing of the apoprotein. This provides an explanation to why the succinate dehydrogenase synthesized in E. coli is not functional and demonstrates that host-specific factors regulate the coenzyme attachment.
mesh_terms: D000595:Amino Acid Sequence; D001412:Bacillus subtilis / Q000201:enzymology* / Q000235:genetics; D001483:Base Sequence; D002462:Cell Membrane / Q000201:enzymology; D003573:Cytochrome b Group / Q000235:genetics / Q000378:metabolism*; D004269:DNA, Bacterial / Q000235:genetics; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics; D005415:Flavins / Q000378:metabolism; D019255:NADPH Oxidases; D010446:Peptide Fragments; D011499:Protein Processing, Post-Translational; D013385:Succinate Dehydrogenase / Q000235:genetics / Q000378:metabolism*
chemical_list: D003573:Cytochrome b Group; D004269:DNA, Bacterial; D005415:Flavins; D010446:Peptide Fragments; C036888:cytochrome b558; D013385:Succinate Dehydrogenase; D019255:NADPH Oxidases