Kaur Harbinder, Lynn Andrew M
School of Computational and Integrative Sciences, Jawaharlal Nehru University, New Delhi, India.
Front Genet. 2023 Jan 4;13:1010870. doi: 10.3389/fgene.2022.1010870. eCollection 2022.
Cytokinesis is an essential process in bacterial cell division, and it involves more than 25 essential/non-essential cell division proteins that form a protein complex known as a divisome. Central to the divisome are the proteins FtsB and FtsL binding to FtsQ to form a complex FtsQBL, which helps link the early proteins with late proteins. The FtsQBL complex is highly conserved as a component across bacteria. Pathogens like , , , and are the causative agents of the bacterial Neglected Tropical Diseases Cholera, Buruli ulcer, Leprosy, and Trachoma, respectively, some of which seemingly lack known homologs for some of the FtsQBL complex proteins. In the absence of experimental characterization, either due to insufficient resources or the massive increase in novel sequences generated from genomics, functional annotation is traditionally inferred by sequence similarity to a known homolog. With the advent of accurate protein structure prediction methods, features both at the fold level and at the protein interaction level can be used to identify orthologs that cannot be unambiguously identified using sequence similarity methods. Using the FtsQBL complex proteins as a case study, we report potential remote homologs using Profile Hidden Markov models and structures predicted using AlphaFold. Predicted ortholog structures show conformational similarity with corresponding . proteins irrespective of their level of sequence similarity. Alphafold multimer was used to characterize remote homologs as FtsB or FtsL, when they were not sufficiently distinguishable at both the sequence or structure level, as their interactions with FtsQ and FtsW play a crucial role in their function. The structures were then analyzed to identify functionally critical regions of the proteins consistent with their homologs and delineate regions potentially useful for inhibitor discovery.
胞质分裂是细菌细胞分裂中的一个重要过程,它涉及25种以上的必需/非必需细胞分裂蛋白,这些蛋白形成一种称为分裂体的蛋白质复合物。分裂体的核心是FtsB和FtsL蛋白与FtsQ结合形成复合物FtsQBL,它有助于将早期蛋白与晚期蛋白连接起来。FtsQBL复合物作为细菌中的一个组成部分高度保守。诸如霍乱弧菌、溃疡分枝杆菌、麻风分枝杆菌和沙眼衣原体等病原体分别是细菌性被忽视热带病霍乱、布鲁里溃疡、麻风病和沙眼的病原体,其中一些病原体似乎缺乏某些FtsQBL复合物蛋白的已知同源物。在缺乏实验表征的情况下,要么是由于资源不足,要么是由于基因组学产生的新序列大量增加,传统上通过与已知同源物的序列相似性来推断功能注释。随着精确蛋白质结构预测方法的出现,折叠水平和蛋白质相互作用水平的特征都可用于识别使用序列相似性方法无法明确识别的直系同源物。以FtsQBL复合物蛋白为例,我们使用Profile隐马尔可夫模型和AlphaFold预测的结构报告了潜在的远缘同源物。预测的直系同源物结构显示出与相应的……蛋白具有构象相似性,无论它们的序列相似性水平如何。当远缘同源物在序列或结构水平上都无法充分区分时,使用AlphaFold多聚体将其表征为FtsB或FtsL,因为它们与FtsQ和FtsW的相互作用在其功能中起着关键作用。然后对这些结构进行分析以确定与它们的同源物一致的蛋白质功能关键区域,并描绘出可能对抑制剂发现有用的区域。