Chen R, Perrone C A, Amos L A, Linck R W
University of Minnesota, Department of Cell Biology and Neuroanatomy, Minneapolis 55455.
J Cell Sci. 1993 Nov;106 ( Pt 3):909-18. doi: 10.1242/jcs.106.3.909.
Tektins are a class of proteins that form filamentous polymers in the walls of ciliary and flagellar microtubules, and they may also be present in centrioles, centrosomes and mitotic spindles. We report here the cloning and sequencing of a cDNA for ciliary tektin B1. Comparison of the predicted amino acid sequence of tektin B1 with the previously published sequence for tektin A1 reveals several features that better define this class of proteins. Like tektin A1, the central region of the tektin B1 polypeptide chain is predicted to form a coiled-coil rod, consisting of four major alpha-helical regions that are separated by non-helical linkers. Between the central rod domains of tektins A and B there is a 34%/20% amino acid sequence identity/similarity, including equivalent 50-residue segments containing 36 identities, and a high probability of long-range structural homology. The tektin polypeptide chains are divided into two major segments that have significant sequence homology to each other, both within a given tektin chain and between tektins A and B, indicative of gene duplication events. The tektins have a secondary structure and molecular design similar to, but a low primary sequence homology with, intermediate filament proteins. Unlike tektin A1, tektin B1 lacks any part of the C-terminal IFP consensus sequence.
纤毛蛋白是一类在纤毛和鞭毛微管壁中形成丝状聚合物的蛋白质，它们也可能存在于中心粒、中心体和有丝分裂纺锤体中。我们在此报告纤毛纤毛蛋白B1的cDNA的克隆和测序。将纤毛蛋白B1的预测氨基酸序列与先前发表的纤毛蛋白A1序列进行比较，揭示了几个能更好地定义这类蛋白质的特征。与纤毛蛋白A1一样，纤毛蛋白B1多肽链的中央区域预计会形成一个卷曲螺旋杆，由四个主要的α螺旋区域组成，这些区域由非螺旋连接体分隔。在纤毛蛋白A和B的中央杆结构域之间，氨基酸序列同一性/相似性为34%/20%，包括包含36个相同残基的等效50个残基片段，以及存在远距离结构同源性的高可能性。纤毛蛋白多肽链分为两个主要部分，它们在给定的纤毛蛋白链内以及纤毛蛋白A和B之间彼此具有显著的序列同源性，这表明发生了基因复制事件。纤毛蛋白具有与中间丝蛋白相似的二级结构和分子设计，但一级序列同源性较低。与纤毛蛋白A1不同，纤毛蛋白B1缺乏C端中间丝蛋白共有序列的任何部分。
