Structural Basis of a Thiol-Disulfide Oxidoreductase in the Hedgehog-Forming Actinobacterium Corynebacterium matruchotii

Abstract

The actinobacterium has been implicated in nucleation of oral microbial consortia leading to biofilm formation. Due to the lack of genetic tools, little is known about basic cellular processes, including protein secretion and folding, in this organism. We report here a survey of the genome, which encodes a large number of exported proteins containing paired cysteine residues, and identified an oxidoreductase that is highly homologous to the thiol-disulfide oxidoreductase MdbA (MdbA). Crystallization studies uncovered that the 1.2-Å resolution structure of MdbA (MdbA) possesses two conserved features found in actinobacterial MdbA enzymes, a thioredoxin-like fold and an extended α-helical domain. By reconstituting the disulfide bond-forming machine , we demonstrated that MdbA catalyzes disulfide bond formation within the actinobacterial pilin FimA. A new gene deletion method supported that is essential in Remarkably, heterologous expression of MdbA in the Δ mutant rescued its known defects in cell growth and morphology, toxin production, and pilus assembly, and this thiol-disulfide oxidoreductase activity required the catalytic motif CXXC. Altogether, the results suggest that MdbA is a major thiol-disulfide oxidoreductase, which likely mediates posttranslocational protein folding in by a mechanism that is conserved in The actinobacterium has been implicated in the development of oral biofilms or dental plaque; however, little is known about the basic cellular processes in this organism. We report here a high-resolution structure of a oxidoreductase that is highly homologous to the thiol-disulfide oxidoreductase MdbA. By biochemical analysis, we demonstrated that MdbA catalyzes disulfide bond formation Furthermore, a new gene deletion method revealed that deletion of is lethal in Remarkably, MdbA can replace MdbA to maintain normal cell growth and morphology, toxin production, and pilus assembly. Overall, our studies support the hypothesis that utilizes MdbA as a major oxidoreductase to catalyze oxidative protein folding.

Cell-to-cell interaction requires optimal positioning of a pilus tip adhesin modulated by gram-positive transpeptidase enzymes

“…All statistical analysis was performed using GraphPad Prism 5.0 as previously reported, with significant differences determined using the unpaired t test with Welch's correction and a nonparametric, 2-tailed value for P of ≤0.05, ≤0.01, or 0.001 considered significant (55).…”

Metabolic Current Production by an Oral Biofilm Pathogen Corynebacterium matruchotii

“…In comparison to conventional techniques involving the microscopic observation of cells, complex sensor systems, and longer cultivation time assays [ 29 , 30 ], our SA strategy can be simple and effective. Moreover, C. matruchotii is known for the initiation of oral microbial consortia leading to biofilm formation ranges in size from a few tens to a few hundreds of microns in radius [ 31 , 32 ] and also we observed a multilayered biofilm on the electrode surface in our study by SEM ( Figure 2 A), while researchers have attributed the decreased antibiotic susceptibility to the reduced antibiotic penetration in biofilms, thus new antimicrobial drugs are in demand, which can enhance their penetration and reach to the bottom of colonized cells [ 33 ]. In this regard, our electrochemical platform could also be very effective, because electroactive pathogens may favor growth at the biofilm-electrode interface, and most active cells may be found at the electrode surface [ 34 ]; thus, the efficiency of drug’s penetration can be analyzed with electrochemical activity.…”

Effect of Periodontal Disease-associated Bacteria on the Formation of Dental Calculus: An In Vitro Study

“…29 It was thought that C. matruchotii could not sustain its viability and, therefore, degenerated and calcified. 29 In our study, C. matruchotii was inoculated on a content-rich medium and maintained bacterial viability. Therefore, in the studied medium, bacteria did not degenerate, did not lose their viability, and were not calcified.…”