Contribution of cationic amino acids toward the inhibition of Arg-specific cysteine proteinase (Arg-gingipain) by the antimicrobial dodecapeptide, CL(14-25), from rice protein

• Published in: Biopolymers Vol. 102; no. 5; pp. 379 - 389
• Main Authors: Taniguchi, Masayuki, Matsuhashi, Yoshiyasu, Abe, Takako K., Ishiyama, Yohei, Saitoh, Eiichi, Kato, Tetsuo, Ochiai, Akihito, Tanaka, Takaaki
• Format: Journal Article
• Language: English
• Published: United States Blackwell Publishing Ltd 01.09.2014
• Subjects: Adhesins, Bacterial - metabolism; Amino Acid Sequence; Amino acids; Amino Acids - metabolism; Analogs; Anti-Infective Agents - pharmacology; Antiinfectives and antibacterials; antimicrobial peptide; Arg-gingipain inhibitor; bifunctional peptide; Biopolymers; Cationic; cationic peptide; Chromatography, High Pressure Liquid; Chromatography, Reverse-Phase; Cysteine Endopeptidases - metabolism; Inhibition; inhibition in a mixed manner; Inhibitors; Inhibitory Concentration 50; Kinetics; Molecular Sequence Data; Oryza - chemistry; Oryza sativa; Peptide Fragments - chemistry; Peptide Fragments - pharmacology; Peptides - chemistry; Peptides - pharmacology; Plant Proteins - pharmacology; Porphyromonas gingivalis; Protease Inhibitors - pharmacology; Residues; cationic peptide; Arg-gingipain inhibitor; antimicrobial peptide; inhibition in a mixed manner; bifunctional peptide
• ISSN: 0006-3525; 1097-0282
• DOI: 10.1002/bip.22525

ABSTRACT CL(14–25), a dodecapeptide, exhibits antimicrobial activity against Porphyromonas gingivalis with the 50% growth‐inhibitory concentration (IC50) value of 145 µM, and arginine‐specific gingipain (Rgp)‐inhibitory activity. Kinetic analysis revealed that CL(14–25) is a mixed‐type inhibitor, with inhibition constants (Ki and Ki′ values) of 1.4 × 10−6 M and 4.3 × 10−6 M, respectively. To elucidate the contributions of four cationic amino acid residues at the N‐ and C‐termini of CL(14–25) toward Rgp‐inhibitory activity, we investigated the Rgp‐inhibitory activities of truncated and alanine‐substituted analogs of CL(14–25). Rgp‐inhibitory activities significantly decreased by truncated analogs, CL(15–25) and CL(16–25), whereas those of CL(14–24) and CL(14–23) were almost as high as that of CL(14–25). Rgp‐inhibitory activities of alanine‐substituted analogs, CL(R14A) and CL(R14A, R15A) also significantly decreased, whereas those of CL(K25A) and CL(R24A, K25A) were higher than that of CL(14–25). These results suggest that the arginine residue at position 15 substantially contributes to the Rgp‐inhibitory activity and that the arginine residue at position 14 plays important roles in exerting Rgp‐inhibitory activity. In this study, we demonstrated that CL(K25A) was a potent, dual function, peptide inhibitor candidate, exhibiting Rgp‐inhibitory activity with Ki and Ki′ of 9.6 × 10−7 M and 1.9 × 10−6 M, respectively, and antimicrobial activity against P. gingivalis with an IC50 value of 51 µM. © 2014 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 102: 379–389, 2014.