Satomura Takenori, Hara Yusuke, Suye Shin-ichiro, Sakuraba Haruhiko, Ohshima Toshihisa
Department of Applied Chemistry and Biotechnology, Graduate School of Engineering, University of Fukui, Bunkyo, Fukui, Japan.
Biosci Biotechnol Biochem. 2012;76(3):589-93. doi: 10.1271/bbb.110775.
A third novel type of dye-linked L-proline dehydrogenase (LPDH) has recently been found in the hyperthermophilic archaeon, Pyrobaculum calidifontis, by Satomura et al. The gene encoding the enzyme homologue was identified in the aerobic hyperthermophilic archaeon, Aeropyrum pernix. The gene was successfully expressed in Escherichia coli, and the product was purified to homogeneity and characterized. The expressed enzyme was highly thermostable LPDH having a molecular mass of about 88 kDa and a homodimeric structure. The preferred substrate for the enzyme was L-proline with 2,6-dichloroindophenol (DCIP) as the electron acceptor. However, the enzyme did not utilize ferricyanide as the electron acceptor, in contrast to all other known LPDHs. The electrochemical determination of L-proline at concentrations from 0 to 0.7 mM was achieved by using A. pernix LPDH. A phylogenetic analysis revealed A. pernix LPDH to be clustered with the third type of LPDHs, and to be clearly separated from the clusters of previously known heterooligomeric LPDHs.
最近，Satomura等人在嗜热古菌嗜热栖热袍菌中发现了第三种新型的染料连接L-脯氨酸脱氢酶（LPDH）。在嗜氧嗜热古菌火球菌中鉴定出了编码该酶同源物的基因。该基因在大肠杆菌中成功表达，其产物被纯化至同质并进行了表征。所表达的酶是一种高度耐热的LPDH，分子量约为88 kDa，具有同型二聚体结构。该酶的首选底物是L-脯氨酸，以2,6-二氯靛酚（DCIP）作为电子受体。然而，与所有其他已知的LPDH不同，该酶不利用铁氰化物作为电子受体。通过使用火球菌LPDH实现了对浓度为0至0.7 mM的L-脯氨酸的电化学测定。系统发育分析表明，火球菌LPDH与第三种类型的LPDH聚集在一起，并且与先前已知的异源寡聚LPDH的簇明显分开。
