ABSTRACT

Background: The cell-surface cysteine proteinases RgpA, RgpB (Arg-gingipain), and Kgp (Lys-gingipain) are major virulence factors of P. gingivalis, a keystone pathogen in the development of destructive periodontal disease. The gingipains function as proteinases and transpeptidases utilising small peptides such as glycylglycine as acceptor molecules. However, the characteristics of the gingipains from most P. gingivalis strains have not been determined.

Methods: We determined the phenotypes of a panel of P. gingivalis laboratory strains and global clinical isolates with respect to growth on blood agar plus whole-cell and vesicle-free culture supernatant (VFSN) Arg- and Lys-specific proteinase activities.

Results: The P. gingivalis isolates exhibited different growth characteristics and hydrolysis of haemoglobin in solid media. Whole-cell Arg-gingipain Vmax varied 5.8-fold and the whole cell Lys-gingipain V_max varied 2.1-fold across the strains. Furthermore, the P. gingivalis strains showed more than 107-fold variance in soluble Arg-gingipain activity in VFSN and more than 371-fold variance in soluble Lys-gingipain activity in VFSN. Glycylglycine and cysteine stimulated Arg- and Lys-specific cleavage activities of all strains. The stimulation by cysteine was in addition to its redox effect consistent with both glycylglycine and cysteine promoting transpeptidation.

Conclusion: The global P. gingivalis clinical isolates exhibit different Arg- and Lys‑gingipain activities with substantial variability in the level of soluble proteinases released into the environment.

摘要

背景：细胞表面半胱氨酸蛋白酶RgpA，RgpB（Arg-gingipain）和Kgp（Lys-gingipain）是牙龈卟啉单胞菌的主要毒力因子，P.gingivalis是破坏性牙周病发展的关键病原体。姜黄素起着蛋白酶和转肽酶的作用，利用小肽如甘氨酰甘氨酸作为受体分子。然而，尚未确定来自大多数齿龈假单胞菌菌株的齿龈蛋白酶的特征。

方法：关于血琼脂上的生长以及全细胞和无囊培养物上清液（VFSN）Arg和Lys特异性蛋白酶活性，我们确定了一组牙龈卟啉单胞菌实验室菌株和全球临床分离株的表型。

结果：在牙龈卟啉菌分离株显示出不同的生长特性和在固体培养基血红蛋白的水解。在整个菌株中，全细胞Arg-gingipain Vmax变化5.8倍，而全细胞Lys-gingipain _Vmax变化2.1倍。此外，牙龈卟啉单胞菌菌株在VFSN中显示出可溶性Arg-gingipain活性变化超过107倍，在VFSN中显示出可溶性Lys-gingipain活性变化超过371倍。甘氨酰甘氨酸和半胱氨酸刺激所有菌株的Arg和Lys特异性切割活性。半胱氨酸的刺激除了其氧化还原作用外，还与甘氨酰甘氨酸和半胱氨酸促进转肽作用一致。

结论：全球牙龈卟啉单胞菌临床分离株表现出不同的Arg-和Lys-gingipain活性，并且释放到环境中的可溶性蛋白酶水平存在很大差异。