Laboratory for Molecular Sensing, IBP-CNR, Naples, Italy.
Gene. 2010 Aug 1;461(1-2):26-31. doi: 10.1016/j.gene.2010.04.004. Epub 2010 Apr 18.
The gene encoding a novel alcohol dehydrogenase (ADH) that belongs to the medium chain dehydrogenase/reductase (MDR) superfamily was identified in the hyperthermophilic archaeon, Pyrobaculum aerophilum. The P. aerophilum ADH gene (Pae2687) was over-expressed in Escherichia coli, and the protein (PyAeADHII) was purified to homogeneity and characterized. The PyAeADHII belongs to a medium chain class because its monomer size is 330 residues and even if it is structurally similar to other enzymes belonging to MDR superfamily, it lacks key residues involved in the coordination of the catalytic Zn ion and in the binding of alcoholic substrates typical of other ADHs. Consistently, PyAeADHII does not show activity on a large number of alcohols, aldheydes or ketones. It is active only when alpha-tetralone is used as a substrate. The enzyme has a strict requirement for NADP(H) as the coenzyme and has remarkable thermophilicity, displaying activity at temperatures up to 95 degrees C. The study of the metabolic pathways of P. aerophilum can provide information on the evolution of genes and enzymes and may be crucial for understanding the evolution of eukaryotic cells.
一种新型醇脱氢酶（ADH）的基因在嗜热古菌 Pyrobaculum aerophilum 中被鉴定出来，该基因属于中链脱氢酶/还原酶（MDR）超家族。嗜热古菌 Pyrobaculum aerophilum 的 ADH 基因（Pae2687）在大肠杆菌中过表达，得到的蛋白质（PyAeADHII）被纯化至均一性并进行了表征。PyAeADHII 属于中链类，因为其单体大小为 330 个残基，即使它在结构上与属于 MDR 超家族的其他酶相似，但它缺乏参与催化 Zn 离子配位和结合其他 ADHs 典型醇类底物的关键残基。一致地，PyAeADHII 对大量醇、醛或酮没有活性。只有当使用α-四氢萘酮作为底物时，该酶才具有活性。该酶对 NADP（H）作为辅酶有严格的要求，并且具有显著的耐热性，在高达 95°C 的温度下具有活性。对 Pyrobaculum aerophilum 代谢途径的研究可以提供有关基因和酶进化的信息，对于理解真核细胞的进化可能至关重要。
