Undergraduate Research Project, College of Natural and Agricultural Sciences, University of California Riverside, Riverside, CA, USA.
Graduate Program in Genetics, Genomics and Bioinformatics, University of California Riverside, Riverside, CA, USA; Division of Biomedical Sciences, School of Medicine, University of California Riverside, Riverside, CA, USA.
J Struct Biol. 2023 Sep;215(3):108011. doi: 10.1016/j.jsb.2023.108011. Epub 2023 Aug 9.
Leucine Rich Repeat (LRR) domains, are present in hundreds of thousands of proteins across all kingdoms of life and are typically involved in protein-protein interactions and ligand recognition. LRR domains are classified into eight classes and when examined in three dimensions seven, of them form curved solenoid-like super-helices, also described as toruses, with a beta sheet on the concave (inside) and stacked alpha-helices on the convex (outside) of the torus. Here we present an overview of the least characterized 8th class of LRR proteins, the TpLRR-like LRRs, named after the Treponema pallidum protein Tp0225. Proteins from the TpLRR class differ from the proteins in all other known LRR classes by having a flipped curvature, with the beta sheet on the convex side of the torus and irregular secondary structure instead of helices on the opposite, now concave site. TpLRR proteins also present highly divergent sequence pattern of individual repeats and can associate with specific types of additional domains. Several of the characterized proteins from this class, specifically the BspA-like proteins, were found in human bacterial and protozoan pathogens, playing an important role in the interactions between the pathogens and the host immune system. In this paper we surveyed all existing experimental structures and selected AlphaFold models of the best-known proteins containing this class of LRR repeats, analyzing the relation between the pattern of conserved residues, specific structural features and functions of these proteins.
富含亮氨酸重复（LRR）结构域存在于所有生命领域的数十万种蛋白质中，通常参与蛋白质-蛋白质相互作用和配体识别。LRR 结构域分为八个类别，当从三维角度研究时，其中七个形成弯曲的类似螺旋的超螺旋，也称为环，β 片层在环的凹面（内部），堆积的α-螺旋在凸面（外部）。在这里，我们概述了 least characterized 第八类 LRR 蛋白，TpLRR 样 LRRs，以梅毒螺旋体蛋白 Tp0225 命名。TpLRR 类蛋白与所有其他已知 LRR 类蛋白的区别在于曲率翻转，β 片层在环的凸面，相反的现在凹面的二级结构不是螺旋。TpLRR 蛋白还呈现出高度不同的单个重复序列模式，并可以与特定类型的附加结构域相关联。该类别的几个已鉴定的蛋白，特别是 BspA 样蛋白，存在于人类细菌和原生动物病原体中，在病原体与宿主免疫系统的相互作用中发挥着重要作用。在本文中，我们调查了所有现有的实验结构，并选择了含有这种 LRR 重复的最佳已知蛋白的 AlphaFold 模型，分析了保守残基模式、特定结构特征和这些蛋白功能之间的关系。
