JBIC Journal of Biological Inorganic Chemistry ( IF 2.7 ) Pub Date : 2020-11-01 , DOI: 10.1007/s00775-020-01833-9 Breeanna Mintmier 1 , Jennifer M McGarry 1 , Daniel J Bain 2 , Partha Basu 1
|
Abstract
The molybdopterin enzyme family catalyzes a variety of substrates and plays a critical role in the cycling of carbon, nitrogen, arsenic, and selenium. The dimethyl sulfoxide reductase (DMSOR) subfamily is the most diverse family of molybdopterin enzymes and the members of this family catalyze a myriad of reactions that are important in microbial life processes. Enzymes in the DMSOR family can transform multiple substrates; however, quantitative information about the substrate preference is sparse, and, more importantly, the reasons for the substrate selectivity are not clear. Molybdenum coordination has long been proposed to impact the catalytic activity of the enzyme. Specifically, the molybdenum-coordinating residue may tune substrate preference. As such, molybdopterin enzyme periplasmic nitrate reductase (Nap) is utilized as a vehicle to understand the substrate preference and delineate the kinetic underpinning of the differences imposed by exchanging the molybdenum ligands. To this end, NapA from Campylobacter jejuni has been heterologously overexpressed, and a series of variants, where the molybdenum coordinating cysteine has been replaced with another amino acid, has been produced. The kinetic properties of these variants are discussed and compared with those of the native enzyme, providing quantitative information to understand the function of the molybdenum-coordinating residue.
Graphic abstract
中文翻译：
DMSO 还原酶家族中钼的内源性配体的动力学后果：周质硝酸还原酶的案例研究
摘要
钼蝶呤酶家族催化多种底物，并在碳、氮、砷和硒的循环中起关键作用。二甲基亚砜还原酶 (DMSOR) 亚家族是钼蝶呤酶家族中最多样化的家族，该家族的成员催化了无数在微生物生命过程中很重要的反应。DMSOR 家族中的酶可以转化多种底物；然而，关于底物偏好的定量信息很少，更重要的是，底物选择性的原因尚不清楚。长期以来，人们一直认为钼配位会影响酶的催化活性。具体而言，钼配位残基可以调节底物偏好。像这样，钼蝶呤酶周质硝酸盐还原酶 (Nap) 被用作了解底物偏好和描绘由交换钼配体所施加的差异的动力学基础的载体。为此，NapA 从空肠弯曲杆菌已异源过度表达，并产生了一系列变体，其中钼配位半胱氨酸已被另一种氨基酸取代。讨论了这些变体的动力学特性，并与天然酶的动力学特性进行了比较，提供了定量信息以了解钼配位残基的功能。
京公网安备 11010802027423号