Abstract Prevotella intermedia, a Gram-negative anaerobic rod, is frequently observed in subgingival polymicrobial biofilms from adults with chronic periodontitis. Peptidases in periodontopathic bacteria are considered to function as etiological reagents. Prevotella intermedia OMA14 cells abundantly express an unidentified cysteine peptidase specific for Arg-4-methycoumaryl-7-amide (MCA). BAU17746 (locus tag, PIOMA14_I_1238) and BAU18827 (locus tag, PIOMA14_II_0322) emerged as candidates of this peptidase from the substrate specificity and sequence similarity with C69-family Streptococcus gordonii Arg-aminopeptidase. The recombinant form of the former solely exhibited hydrolyzing activity toward Arg-MCA, and BAU17746 possesses a 26.6% amino acid identity with the C69-family Lactobacillus helveticus dipeptidase A. It was found that BAU17746 as well as L. helveticus dipeptidase A was a P1-position Arg-specific dipeptidase A, although the L. helveticus entity, a representative of the C69 family, had been reported to be specific for Leu and Phe. The full-length form of BAU17746 was intramolecularly processed to a mature form carrying the N-terminus of Cys15. In conclusion, the marked Arg-MCA-hydrolyzing activity in Pre. intermedia was mediated by BAU17746 belonging to the C69-family dipeptidase A, in which the mature form carries an essential cysteine at the N-terminus.

中文翻译：

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Prevotella intermedia 中二肽酶 A​​ 的底物特异性表征和新的自动加工机制

摘要 Prevotella intermedia 是一种革兰氏阴性厌氧菌，经常在患有慢性牙周炎的成人牙龈下多微生物生物膜中观察到。牙周病细菌中的肽酶被认为起到病原体的作用。Prevotella intermedia OMA14 细胞大量表达对 Arg-4-methycoumaryl-7-amide (MCA) 特异的未知半胱氨酸肽酶。BAU17746（基因座标签，PIOMA14_I_1238）和 BAU18827（基因座标签，PIOMA14_II_0322）由于底物特异性和与 C69 家族 Streptococcus gordonii Arg-氨基肽酶的序列相似性而成为该肽酶的候选者。前者的重组形式仅表现出对 Arg-MCA 的水解活性，BAU17746 与 C69 家族瑞士乳杆菌二肽酶 A​​ 具有 26.6% 的氨基酸同一性。发现 BAU17746 以及瑞士乳杆菌二肽酶 A​​ 是 P1 位 Arg 特异性二肽酶 A​​，尽管据报道瑞士乳杆菌实体（C69 家族的代表）对 Leu 和 Phe 具有特异性。BAU17746 的全长形式被分子内加工成携带 Cys15 的 N 端的成熟形式。总之，Pre中显着的Arg-MCA水解活性。intermedia 由属于 C69 家族二肽酶 A​​ 的 BAU17746 介导，其中成熟形式在 N 端携带必需的半胱氨酸。BAU17746 的全长形式被分子内加工成携带 Cys15 的 N 端的成熟形式。总之，Pre中显着的Arg-MCA水解活性。intermedia 由属于 C69 家族二肽酶 A​​ 的 BAU17746 介导，其中成熟形式在 N 端携带必需的半胱氨酸。BAU17746 的全长形式被分子内加工成携带 Cys15 的 N 端的成熟形式。总之，Pre中显着的Arg-MCA水解活性。intermedia 由属于 C69 家族二肽酶 A​​ 的 BAU17746 介导，其中成熟形式在 N 端携带必需的半胱氨酸。