FEMS Microbiology Letters 82 (1991) 253-256 © 1991 Federation of European Microbiological Societies 0378-1097/91/$03.50 Published by Elsevier ADONIS 037810979100383W 253 FEMSLE 04578 Binding of a histidine-rich peptide to Porphyromonas gingivalis Yukitaka Murakami 1, Satoshi Shizukuishi 1, Akira Tsunemitsu 1, Kazuhisa Nakashima 2, Yukio Kato 2 and Saburo Aimoto 3 l Department of Precentit,e Dentistry, 2 Department of Biochemistry, Faculty of Dentistry, and s Institute for Protein Research, Osaka University, Osaka, Japan Received 26 March 1991 Revision received 24 May 1991 Accepted 27 May 1991 Key words: Histatin; Porphyromonas gingivalis; Scatchard analysis 1. SUMMARY Porphyromonas gingivalis 381 cells were incu- bated with a25I-histidine-rich polypeptide (hista- tin) 5 in the presence or absence of unlabeled histatin 5, to evaluate the histatin-binding capac- ity of the cells. The binding of histatin 5 was rapid, reversible, saturable and specific. The number of histatin 5-binding sites per cell was 3600, and the dissociation constant (K d) was in the order of 10 -6 M. These findings suggest that histatin interacts with certain bacterial cells through specific binding sites on their surface, and will allow the development of a histatin ra- dioreceptor assay. 2. INTRODUCTION Many novel families of histidine-rich polypep- tides (HRPs) are present in human saliva and Correspondence to: A. Tsunemitsu, Department of Preventive Dentistry, Faculty of Dentistry, Osaka University, 1-8 Yamadaoka, Suita, Osaka 565, Japan. salivary glands [1-3]. The HRPs have been shown to inhibit the growth of Candida albicans [4-9] and Streptococcus mutans [10] in vitro. In 1988, Oppenheim et al. named HRP histatin [5]. Trox- ler et al. have shown that there are at least twelve histatins in human parotid secretion, and that the sequence of Lys-Phe-His-Glu-Lys-His-His-Ser- His-Arg is common in various histatins (histatins 1-10) [11]. Porphyromonas ( Bacteroides ) gingivalis is thought to be the most important etiological agent of adult periodontitis in humans [12,13]. Previous studies have demonstrated that P. gingivalis ceils exhibit pathogenicity in vivo, and that the bacte- rial cells produce several virulence factors, such as proteases and hemagglutinin [14-16]. Hemag- glutinating activity of P. gingivalis has been inves- tigated as a parameter that affects the adherence of this bacterium to ceils of oral tissues [17]. More recently, Murakami et al. have pointed out that hemagglutinating activity of P. gingivalis 381 is strongly inhibited by synthetic histatin 5 [18]. However, it remained unclear whether his- tatin 5 actually binds to P. gingivalis cells. We report here that P. gingivalis cells have a single class of histatin 5 receptor. Downloaded from https://academic.oup.com/femsle/article/82/3/253/562801 by guest on 24 November 2023