Bibel M, Brettl C, Gosslar U, Kriegshäuser G, Liebl W
Lehrstuhl für Mikrobiologie, Technische Universität München, Germany.
FEMS Microbiol Lett. 1998 Jan 1;158(1):9-15. doi: 10.1111/j.1574-6968.1998.tb12793.x.
In addition to the previously identified 4-alpha-glucanotransferase gene mgtA and the alpha-amylase gene amyA of Thermotoga maritima strain MSB8 we have now isolated three further genes encoding amylolytic enzymes from a gene library of this ancestral bacterium. The genes code for the extremely thermostable enzymes pullulanase (pulA), maltodextrin phosphorylase (agpA) and alpha-glucosidase (aglA) and have the potential to encode polypeptides with calculated molecular masses of 96.3 kDa, 96.1 kDa and 52.5 kDa, respectively. Comparative amino acid sequence analysis revealed that PulA and AgpA are clearly related to other known enzymes with similar function. AglA, on the other hand, was not related to other alpha-glucosidases but appears to belong to an enzyme family containing alpha-galactosidases and 6-phospho-beta-glucosidases. Enzyme properties are reported which demonstrate the extreme thermostability of these T. maritima enzymes.
除了先前鉴定出的嗜热栖热菌MSB8菌株的4-α-葡聚糖转移酶基因mgtA和α-淀粉酶基因amyA之外，我们现在从这种原始细菌的基因文库中又分离出了另外三个编码淀粉分解酶的基因。这些基因编码极度耐热的酶，即支链淀粉酶（pulA）、麦芽糖糊精磷酸化酶（agpA）和α-葡萄糖苷酶（aglA），并且有可能编码计算分子量分别为96.3 kDa、96.1 kDa和52.5 kDa的多肽。氨基酸序列比较分析表明，PulA和AgpA与其他具有相似功能的已知酶明显相关。另一方面，AglA与其他α-葡萄糖苷酶无关，但似乎属于一个包含α-半乳糖苷酶和6-磷酸-β-葡萄糖苷酶的酶家族。本文报道了这些嗜热栖热菌酶的极端耐热性的酶学性质。
