Koch Christian, Neumann Piotr, Valerius Oliver, Feussner Ivo, Ficner Ralf
Department of Plant Biochemistry, Albrecht-von-Haller-Institute, Georg-August-University Goettingen, Justus-von-Liebig-Weg 11, 37077, Goettingen, Germany.
Georg-August-University Goettingen, Goettingen Center for Molecular Biosciences (GZMB), Justus-von-Liebig-Weg 11, 37077, Goettingen, Germany.
PLoS One. 2016 Feb 23;11(2):e0149846. doi: 10.1371/journal.pone.0149846. eCollection 2016.
FAD-dependent alcohol oxidases (AOX) are key enzymes of methylotrophic organisms that can utilize lower primary alcohols as sole source of carbon and energy. Here we report the crystal structure analysis of the methanol oxidase AOX1 from Pichia pastoris. The crystallographic phase problem was solved by means of Molecular Replacement in combination with initial structure rebuilding using Rosetta model completion and relaxation against an averaged electron density map. The subunit arrangement of the homo-octameric AOX1 differs from that of octameric vanillyl alcohol oxidase and other dimeric or tetrameric alcohol oxidases, due to the insertion of two large protruding loop regions and an additional C-terminal extension in AOX1. In comparison to other alcohol oxidases, the active site cavity of AOX1 is significantly reduced in size, which could explain the observed preference for methanol as substrate. All AOX1 subunits of the structure reported here harbor a modified flavin adenine dinucleotide, which contains an arabityl chain instead of a ribityl chain attached to the isoalloxazine ring.
依赖黄素腺嘌呤二核苷酸的醇氧化酶（AOX）是甲基营养型生物的关键酶，这类生物能够利用低级伯醇作为唯一的碳源和能源。在此，我们报道了来自巴斯德毕赤酵母的甲醇氧化酶AOX1的晶体结构分析。通过分子置换结合使用Rosetta模型完成和针对平均电子密度图进行松弛的初始结构重建，解决了晶体学相位问题。同八聚体AOX1的亚基排列不同于八聚体香草醇氧化酶以及其他二聚体或四聚体醇氧化酶，这是由于AOX1中插入了两个大的突出环区域以及一个额外的C末端延伸。与其他醇氧化酶相比，AOX1的活性位点腔尺寸显著减小，这可以解释观察到的对甲醇作为底物的偏好。此处报道的结构中的所有AOX1亚基都含有一种修饰的黄素腺嘌呤二核苷酸，其在异咯嗪环上连接的是阿拉伯糖链而非核糖醇链。
