Satyamjayatu: The Science & Ethics Foundation, Snehatheeram, Shoranur-2 (PO), Kerala 679122, India.
Biochim Biophys Acta Biomembr. 2022 Oct 1;1864(10):183981. doi: 10.1016/j.bbamem.2022.183981. Epub 2022 Jun 8.
The advent of improved structural biology protocols and bioinformatics methodologies have provided paradigm-shifting insights on metabolic or physiological processes catalyzed by homo-/hetero- proteins (super)complexes embedded in phospholipid membranes of cells/organelles. In this panoramic review, we succinctly elucidate the structural features of select redox proteins from four systems: hepatocyte/adrenal cortex endoplasmic reticulum (microsomes), inner mitochondrial membrane (cristae), thylakoid membrane (grana), and in the flattened disks of rod/cone cells (in retina). Besides catalyzing fast/crucial (photo)chemical reactions, these proteins utilize the redox-active diatomic gaseous molecule of oxygen, the elixir of aerobic life. Quite contrary to extant perceptions that invoke primarily deterministic affinity-binding or conformation-change based "proton-pump"/"serial electron-relay" type roles, we advocate murzyme functions for the membrane-embedded proteins in these systems. Murzymes are proteins that generate/stabilize/utilize diffusible reactive (oxygen) species (DRS/DROS) based activities. Herein, we present a brief compendium of the recently revealed wealth of structural information and mechanistic concepts on how the membrane proteins use DRS/DROS to aid 'effective charge separation' and facilitate trans-membrane dynamics of diverse species in milieu, thereby enabling the cells to function as 'simple chemical engines'.
改良的结构生物学方案和生物信息学方法的出现，为嵌入细胞/细胞器磷脂膜中的同/异源蛋白质（超）复合物催化的代谢或生理过程提供了具有变革意义的见解。在这篇全景综述中，我们简明扼要地阐述了来自四个系统的精选氧化还原蛋白的结构特征：肝细胞/肾上腺皮质内质网（微粒体）、线粒体内膜（嵴）、类囊体膜（基质片层）和杆/锥细胞的扁平盘（视网膜）。除了催化快速/关键的（光）化学反应外，这些蛋白质还利用氧化还原活性双原子气态分子氧气，这是需氧生命的灵丹妙药。与主要基于亲和力结合或构象变化的现有观念形成鲜明对比的是，我们主张这些系统中的膜嵌入蛋白具有 murzyme 功能。murzyme 是指产生/稳定/利用可扩散反应性（氧）物种（DRS/DROS）的蛋白质。在此，我们简要介绍了最近揭示的大量结构信息和机制概念，这些信息和概念说明了膜蛋白如何利用 DRS/DROS 来辅助“有效电荷分离”并促进环境中多种物质的跨膜动力学，从而使细胞能够作为“简单的化学发动机”发挥作用。
