Silvennoinen Laura, Sandalova Tatyana, Schneider Gunter
Department of Medical Biophysics and Biochemistry, Karolinska Institutet, Stockholm, Sweden.
FEBS Lett. 2009 Sep 3;583(17):2917-21. doi: 10.1016/j.febslet.2009.07.061. Epub 2009 Aug 6.
RemF is a polyketide cyclase involved in the biosynthesis of the aromatic pentacyclic metabolite resistomycin in Streptomyces resistomycificus. The enzyme is a member of a structurally hitherto uncharacterized class of polyketide cyclases. The crystal structure of RemF was determined by SAD and refined to 1.2 A resolution. The enzyme subunit shows a beta-sandwich structure with a topology characteristic for the cupin fold. RemF contains a metal binding site located at the bottom of the predominantly hydrophobic active site cavity. A zinc ion is coordinated to four histidine side chains, and two water molecules in octahedral ligand sphere geometry, highly unusual for zinc binding sites in proteins.
RemF是一种聚酮环化酶，参与抗霉素链霉菌中芳香族五环代谢物抗霉素的生物合成。该酶是一类结构上迄今未被表征的聚酮环化酶的成员。RemF的晶体结构通过单波长反常散射法（SAD）确定，并精修至1.2埃分辨率。该酶亚基呈现出一种具有cupin折叠拓扑特征的β-三明治结构。RemF含有一个位于主要为疏水的活性位点腔底部的金属结合位点。一个锌离子与四个组氨酸侧链以及八面体配体球几何结构中的两个水分子配位，这在蛋白质中的锌结合位点中非常罕见。
