1.8.4.2 C101A site-directed mutagenesis, the mutation of the cysteine at position 101 to alanine results in a high-molecular-weight complex that is positive for MdbA and VKOR by immunoblotting and is absent in other alanine substitution mutants and the C93A/C101A double mutation and after treatment with the reducing agent 2-mercaptoethanol 745224 1.8.4.2 C29S specific activity about 5% of wild-type 762613 1.8.4.2 C46A site-directed mutagenesis 765010 1.8.4.2 C49A site-directed mutagenesis, SdbAC49A forms a mixed disulfide with SpeAC87A 765010 1.8.4.2 C57S site-directed mutagenesis, reduced activity 394863 1.8.4.2 C57S/C60S site-directed mutagenesis, no activity 394863 1.8.4.2 C58S complete loss of oxidoreductase activtiy 741551 1.8.4.2 C60S site-directed mutagenesis, no activity 394863 1.8.4.2 C87S specific activity simiular to wild-type 762613 1.8.4.2 C89A site-directed mutagenesis, the single-cysteine active site variant, SdbAC89A, forms a number of mixed disulfide complexes in the mutant -, 765006 1.8.4.2 C91A/C94A site-directed mutagenesis, catalytically inactive mutant -, 765004 1.8.4.2 C95S complete loss of oxidoreductase activtiy 741551 1.8.4.2 H32PY34R/Q35L/F36I/E37Y active variant 659187 1.8.4.2 H33G the mutant shows a loss of the capacity of the protein to isomerize, or shuffle, incorrect disulfides of scrambled RNase A yielding 10% active RNase A only 725470 1.8.4.2 additional information DsbA and DsbB insertion mutants are sensitive to dithiothreitol and benzylpenicillin or Cd2+, Hg2+ and Zn2+, pleitropic phenotype 394853 1.8.4.2 additional information gene sdbA mutants are defective in autolysis, extracellular DNA (eDNA) release, bacteriocin production, and genetic competence but form more biofilm. Inactivation of sdbA upregulates the CiaRH two-component regulatory system in Streptococcus gordonii, leading to the repression of the ComDE quorum sensing system, which results in the enhanced biofilm formation and the lack of bacteriocin production. The sdbB-ccdA2 mutant produces all of the phenotypes displayed by the sdbA mutant. The sdbB-sgo_1177 mutant is defective in eDNA release and bacteriocin production but not autolysis or genetic competence. The sdbB-ccdA1 mutant is defective in autolysis but not eDNA release, bacteriocin production, or genetic competence. The sgo_1177-ccdA2 mutant is partially defective in autolysis but not in other phenotypes. The ccdA1-ccdA2 mutant is defective only in bacteriocin production. The phenotypes exhibited by the sdbB-ccdA2 mutant are reversed when functional copies of sdbB and ccdA2 are knocked back into the same location on the chromosome. Quantitative realtime PCR analysis of the sdbB-ccdA2 mutant shows that the genes immediately upstream (sgo_1174) and downstream (sgo_1170) of the mutated genes are transcribed, indicating that the mutation does not affect the expression of adjacent genes. The levels of sgo_1174 and sgo_1170 expression are similar between the parent, sdbBccdA2 mutant, and sdbB-ccdA2 knockin mutant -, 765006 1.8.4.2 additional information generation of a sdbA-knockout mutant by insertional inactivation using pG1host5 carrying an internal portion of the gene. SpeA in the culture supernatant remains reduced when gene sdbA is inactivated and restored to the oxidized state when a functional copy of sdbA is returned to the sdbA-knockout mutant. Complementation of sdbA deletion restores SpeA to an oxidized state 765010 1.8.4.2 additional information generation of DsbA- mutants from strain MT1131, which form filamentous and osmosensitive cells at 35°C under Res growth conditions on enriched medium, where bioavailable Cu is limited. In contrast, these mutants grow normally at 25°C, but they produce very low levels of cbb3-Cox. Upon supplementation of the growth media with redox-active chemicals, they can grow normally and produce active cbb3-Cox. Overproduction of the Cu importer CcoA partially restores the cbb3-Cox defect, suggesting defective Cu incorporation into this enzyme in the absence of DsbA. Generation of DsbA- cbb3-Cox- and DsbA- bd-Qox- double mutants. Strain MD20 (1dsbA::kan) is used as a recipient, selecting for antibiotic resistance under growth permissive conditions. The double mutants thus obtained are tested for their temperature sensitive Res growth (ResTs) and Cu2+-suppressible phenotypes on MPYE at 35°C. Appropriate merodiploids are constructed by introducing the plasmids pDsbA, pSenC and pBK69 (CcoA) carrying wild-type alleles of dsbA, senC and ccoA, respectively into the DsbA- and DsbA- SenC-mutants using triparental crosses. Mutants lacking DsbA are able to grow via photosynthesis, albeit at a slower rate, on both enriched and minimal growth media, but can grow by aerobic respiration only on minimal, and not on enriched medium, at normal temperature (35°C). The DsbADELTA mutants revert readily on enriched medium at 35°C to regain Res growth ability. Proteomic analyses show that in the absence of DsbA the protease DegP is overproduced, and that the revertants contain mutations that lower DegP activity. DegP is usually less abundant and acts as a chaperone at lower temperatures. Phenotypes, overview -, 764747 1.8.4.2 additional information heterologous expression of MdbACm in the Corynebacterium diphtheriae DELTAmdbA mutant rescues its known defects in cell growth and morphology, toxin production, and pilus assembly, and this thiol-disulfide oxidoreductase activity requires the catalytic motif CXXC. MdbA gene deletion in Corynebacterium matruchotii by gene replacement method. The Corynebacterium diphtheriae DELTAmdbA mutant is able to grow only at 30°C. This defect is rescued by expression of MdbACd. Expression of MdbACm in this mutant also rescues the growth defect. Generation of a MdbA gene deletion mutant of Corynebacterium matruchotii by gene replacement method -, 765004 1.8.4.2 additional information introduction of the patient mutations (W59C/E87X and W66R) into a human-yeast chimera (hyCOA6) that consists of the bulk of the human protein and the N-terminal 24 amino acid residues of yeast Coa6 to facilitate mitochondrial targeting. The respiratory growth of the knockout mutant coa6DELTA cells is restored by the chimeric mutant hyCOA6, but not by either of the tryptophan variants, suggesting that these missense mutations disrupt COA6 function or expression. The hyCOA6W26C mutant is expressed and localizes to mitochondria, while hyCOA6W33R and the truncated protein hyCOA6E54X are undetectable. Overexpression of the wild-type and mutant alleles of COA6 in control and COA6 patient fibroblasts shows that the W66R variant fails to rescue CcO activity. In contrast, expression of the W59C mutant leads to a partial recovery of CcO activity and COX2 levels 764441 1.8.4.2 P31H/H32A/Y34G/Q35L/F36R/E37Y active variant 659187 1.8.4.2 P31H/H32D/Y34S/Q35E/E37S active variant 659187 1.8.4.2 P31H/H32T/Y34A/Q35S/F36T/E37R inactive variant 659187 1.8.4.2 P31K/Y34P/Q35V/F36P/E37T inactive variant 659187 1.8.4.2 P31R/H32G/Y34N/Q35K/F36L/E37A semi-active variant 659187 1.8.4.2 P31R/H32I/Y34F/F36V/E37P inactive variant 659187 1.8.4.2 P31R/H32S/Y34C/Q35T/F36Y/E37R semi-active variant 659187 1.8.4.2 P31Y/H32E/Y34T/Q35A/F36D/E37H inactive variant 659187 1.8.4.2 W59C/E87X naturally occuring mutation in a human mitochondrial disease patient, mapping onto the COA6 structure. The truncation mutation (E87X) clearly disrupts the CHCH domain by removing a large portion of the protein from helix 2 onward. Mutation W59C is found within the first helix of COA6, where the side chain of the tryptophan faces the bulk solvent. The missense mutation disrupts COA6 function or expression. The patient with the W59C mutation exhibits a severe CcO deficiency in cardiac tissue 764441 1.8.4.2 W66R naturally occuring mutation in a human mitochondrial disease patient, mapping onto the COA6 structure. Mutation W66R is found within the first helix of COA6, where the side chain of the tryptophan faces the bulk solvent. The missense mutation disrupts COA6 function or expression 764441