Reversible redox regulation of specificity of Arg-gingipain B in Porphyromonas gingivalis

• Arg gingipain B (RgpB) is an Arg-specific cysteine proteinase.
• Strain HG66 RgpB shifts to dominant Lys-X activity upon reversible Cys oxidation.
• Association of novel Lys-X activity with a reversible state change of RgpB.
• Novel Lys-X activity of RgpB was distinguishable from Kgp activity.
• The redox-regulated Lys-X activity of RgpB may provide a survival advantage for P. gingivalis.

Arg-gingipain B (RgpB), a major virulence factor secreted by the periodontal pathogen Porphyromonas gingivalis is an Arg-specific cysteine proteinase. By monitoring proteolytic cleavage of a human salivary peptide histatin 5 using MALDI-TOF MS, RgpB purified from P. gingivalis HG66 was found to shift from a dominant Arg-X to dominant Lys-X activity, both in vitro and in vivo, upon reversible cysteine oxidation. Native PAGE analysis revealed the association of novel Lys-X activity with a reversible state change of the oxidized enzyme. The redox-regulated Lys-X activity of RgpB may provide a survival advantage to P. gingivalis against the oxidative host defence.

Structured summary of protein interactionsRgpBcleaveshistatin 5 by protease assay (View Interaction: 1, 2, 3, 4, 5, 6, 7)