Literature summary for 1.8.4.2 extracted from

Luong, T.T.; Reardon-Robinson, M.E.; Siegel, S.D.; Ton-That, H.
Reoxidation of the thiol-disulfide oxidoreductase MdbA by a bacterial vitamin K epoxide reductase in the biofilm-forming actinobacterium actinomyces oris (2017), J. Bacteriol., 199, e00817-16 .

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Protein Variants

Protein Variants	Comment	Organism
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	Actinomyces oris

Localization

Localization	Comment	Organism	GeneOntology No.	Textmining
membrane	membrane-bound enzyme	Actinomyces oris	16020	-

Organism

Organism	UniProt	Comment	Textmining
Actinomyces oris	A0A0M3KL32	-	-

Synonyms

Synonyms	Comment	Organism
MdbA	-	Actinomyces oris
membrane-bound thiol-disulfide oxidoreductase	-	Actinomyces oris
thiol-disulfide oxidoreductase	-	Actinomyces oris

General Information

General Information	Comment	Organism
metabolism	posttranslocational protein folding in the Gram-positive biofilm-forming actinobacterium Actinomyces oris is mediated by membrane-bound thiol-disulfide oxidoreductase, MdbA, which catalyzes oxidative folding of nascent polypeptides transported by the Sec translocon. Reoxidation of MdbA involves a bacterial vitamin K epoxide reductase (VKOR)-like protein that contains four cysteine residues, C93/C101 and C175/C178, with the latter forming a canonical CXXC thioredoxin-like motif. Topological view of the Actinomyces oris membrane-spanning protein VKOR with these four exoplasmic cysteine residues that participate in MdbA reoxidation. Like deletion of the VKOR gene, alanine replacement of individual cysteine residues abrogates polymicrobial interactions and biofilm formation, concomitant with the failure to form adhesive pili on the bacterial surface. Mutational analysis of VKOR function, overview. The C93 residue of VKOR is postulated to form a mixed disulfide bond with MdbA	Actinomyces oris
additional information	VKOR-mediated reactivation of MdbA appears to be conserved in the Actinobacteria. Formation of the MdbA-VKOR mixed disulfide complex requires C93. The signal of this MdbA-VKOR complex is greatly diminished when the sample is treated with 2-mercaptoethanol. The complex is not found when both C93 and C101 are mutated to alanine. The results suggest that when C101 is mutated, VKOR forms a complex with MdbA via the VKOR C93 residue	Actinomyces oris
physiological function	posttranslocational protein folding in the Gram-positive biofilm-forming actinobacterium Actinomyces oris is mediated by membrane-bound thiol-disulfide oxidoreductase, MdbA, which catalyzes oxidative folding of nascent polypeptides transported by the Sec translocon	Actinomyces oris

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Release 2023.1 (January 2023)