Federal Research Center "Pushchino's center of Biological Research", Institute of Basic Biological Problems of Russian Academy of Sciences, Institutskaya st., 2, Pushchino, Moscow region 142290, Russia.
Centre for Environmental Biotechnology, School of Natural Sciences, Bangor University, Bangor LL57 2UW, UK.
Biochim Biophys Acta Bioenerg. 2021 Dec 1;1862(12):148492. doi: 10.1016/j.bbabio.2021.148492. Epub 2021 Sep 4.
Thiocapsa bogorovii BBS (former name Thiocapsa roseopersicina) contains HydSL hydrogenase belonging to 1e subgroup of NiFe hydrogenases (isp-type). The operon of these hydrogenases contains gene for small subunit (hydS), gene for large subunit (hupL), and genes isp1 and isp2 between them. It is predicted that last two genes code electron transport careers for electron transfer from/to HydSL hydrogenase. However, the interaction between them is unclear. The aim of this study was to determine structural and functional role of T. bogorovii HydS C-terminal end. For this purpose, we modelled all subunits of the complex HydS-HydL-Isp1-Isp2. Hydrophobicity surface analysis of the Isp1 model revealed highly hydrophobic helices suggesting potential membrane localization, as well as the hydrophilic C-terminus, which is likely localized outside of membrane. Isp1 model was docked with models of full length and C-terminal truncated HydSL hydrogenases and results illustrate the possibility of HydSL membrane anchoring via transmembrane Isp1 with essential participation of C-terminal end of HydS in the interaction. C-terminal end of HydS subunit was deleted and our studies revealed that the truncated HydSL hydrogenase detached from cellular membranes in contrast to native hydrogenase. It is known that HydSL hydrogenase in T. bogorovii performs the reaction of elemental sulfur reduction (S + H = ≥HS). Cells with truncated HydS produced much less HS in the presence of H and S. Thus, our data support the conclusion that C-terminal end of HydS subunit participates in interaction of HydSL hydrogenase with Isp1 protein for membrane anchoring and electron transfer.
硫帽菌 BBS（原名硫帽菌玫瑰色）含有属于 NiFe 氢化酶 1e 亚组（isp 型）的 HydSL 氢化酶。这些氢化酶的操纵子包含小亚基（hydS）基因、大亚基（hupL）基因以及它们之间的 isp1 和 isp2 基因。据预测，后两个基因编码电子从/到 HydSL 氢化酶的电子传递途径。然而，它们之间的相互作用尚不清楚。本研究旨在确定硫帽菌 HydS C 末端的结构和功能作用。为此，我们对复合物 HydS-HydL-Isp1-Isp2 的所有亚基进行了建模。Isp1 模型的疏水性表面分析显示出高度疏水性的螺旋，表明其可能存在于膜内定位，以及亲水的 C 末端，这很可能位于膜外。Isp1 模型与全长和 C 端截断的 HydSL 氢化酶模型对接，结果表明 HydSL 通过跨膜 Isp1 进行膜锚定的可能性，并且 HydS 的 C 末端在相互作用中起重要作用。我们删除了 HydS 亚基的 C 末端，并发现与天然氢化酶相比，截断的 HydSL 氢化酶从细胞膜上脱离。已知硫帽菌中的 HydSL 氢化酶进行元素硫还原反应（S+H=≥HS）。与 H 和 S 存在时，带有截断 HydS 的细胞产生的 HS 要少得多。因此，我们的数据支持这样的结论，即 HydS 亚基的 C 末端参与 HydSL 氢化酶与 Isp1 蛋白的相互作用，以进行膜锚定和电子转移。
