Saeki Katsuhisa, Magallones Marietta V, Takimura Yasushi, Hatada Yuji, Kobayashi Tohru, Kawai Shuji, Ito Susumu
Tochigi Research Laboratories of Kao Corporation, 2606 Akabane, Ichikai, Haga, Tochigi, 321-3497, Japan.
Curr Microbiol. 2003 Oct;47(4):337-40. doi: 10.1007/s00284-002-4018-9.
The gene for a new subtilisin from the alkaliphilic Bacillus sp. KSM-LD1 was cloned and sequenced. The open reading frame of the gene encoded a 97 amino-acid prepro-peptide plus a 307 amino-acid mature enzyme that contained a possible catalytic triad of residues, Asp32, His66, and Ser224. The deduced amino acid sequence of the mature enzyme (LD1) showed approximately 65% identity to those of subtilisins SprC and SprD from alkaliphilic Bacillus sp. LG12. The amino acid sequence identities of LD1 to those of previously reported true subtilisins and high-alkaline proteases were below 60%. LD1 was characteristically stable during incubation with surfactants and chemical oxidants. Interestingly, an oxidizable Met residue is located next to the catalytic Ser224 of the enzyme as in the cases of the oxidation-susceptible subtilisins reported to date.
从嗜碱芽孢杆菌KSM-LD1中克隆并测序了一种新型枯草杆菌蛋白酶的基因。该基因的开放阅读框编码一个97个氨基酸的前原肽加上一个307个氨基酸的成熟酶，该成熟酶包含一个可能的催化三联体残基，即天冬氨酸32、组氨酸66和丝氨酸224。成熟酶（LD1）推导的氨基酸序列与嗜碱芽孢杆菌LG12的枯草杆菌蛋白酶SprC和SprD的氨基酸序列显示出约65%的同一性。LD1与先前报道的真正枯草杆菌蛋白酶和高碱性蛋白酶的氨基酸序列同一性低于60%。LD1在与表面活性剂和化学氧化剂孵育期间具有特征性的稳定性。有趣的是，与迄今为止报道的易氧化的枯草杆菌蛋白酶一样，该酶的催化丝氨酸224旁边有一个可氧化的甲硫氨酸残基。
