Identification and characterization of novel filament-forming proteins in cyanobacteria
Identification and characterization of novel filament-forming proteins in cyanobacteria
复制标题
蓝藻中新型丝状形成蛋白的鉴定和表征
作者：
B. L. Springstein;Christian Woehle;Julia Weissenbach;A. Helbig;Tal Dagan;Karina Stucken
细菌中的丝状体形成蛋白在蛋白质复合物和复制子的稳定和定位中起作用;因此它们有助于无数细胞过程，如细胞分裂和生长。在这里，我们提出了两个新的毒素形成蛋白的蓝藻。调查蓝藻基因组的卷曲螺旋丰富的蛋白质（CCRPs）预测为推定的毒力形成蛋白，我们观察到较高比例的CCRPs在丝状蓝藻相比，单细胞蓝藻。使用我们的预测，我们确定了9个蛋白质家族与推定的中间丝（IF）的属性。聚合试验显示，在体外形成聚合物的蛋白质和三种蛋白质，在体内形成聚合物。来自Muscicola Fischerella PCC 7414的Fm 7001在体外聚合并在多种生物体内形成细丝。此外，我们确定了一个tetratricopeptide重复蛋白-All 4981-在鱼腥藻属PCC 7120，在体外和体内聚合成细丝。All 4981与已知的细胞骨架蛋白相互作用，是鱼腥藻生存力不可或缺的。虽然Syc 2039在体外不能形成丝状体，但来自细长聚球藻PCC 7942的Syc 2039在体内组装成丝状体，并且Δ Syc 2039突变体的特征在于胞质分裂受损。我们的研究结果扩展了已知的原核生物形成的CCRPs的剧目，并证明蓝藻CCRPs参与细胞形态，运动，胞质分裂和集落完整性。
Filament-forming proteins in bacteria function in stabilization and localization of proteinaceous complexes and replicons; hence they are instrumental for myriad cellular processes such as cell division and growth. Here we present two novel filament-forming proteins in cyanobacteria. Surveying cyanobacterial genomes for coiled-coil-rich proteins (CCRPs) that are predicted as putative filament-forming proteins, we observed a higher proportion of CCRPs in filamentous cyanobacteria in comparison to unicellular cyanobacteria. Using our predictions, we identified nine protein families with putative intermediate filament (IF) properties. Polymerization assays revealed four proteins that formed polymers in vitro and three proteins that formed polymers in vivo. Fm7001 from Fischerella muscicola PCC 7414 polymerized in vitro and formed filaments in vivo in several organisms. Additionally, we identified a tetratricopeptide repeat protein - All4981 - in Anabaena sp. PCC 7120 that polymerized into filaments in vitro and in vivo. All4981 interacts with known cytoskeletal proteins and is indispensable for Anabaena viability. Although it did not form filaments in vitro, Syc2039 from Synechococcus elongatus PCC 7942 assembled into filaments in vivo and a Δsyc2039 mutant was characterized by an impaired cytokinesis. Our results expand the repertoire of known prokaryotic filament-forming CCRPs and demonstrate that cyanobacterial CCRPs are involved in cell morphology, motility, cytokinesis and colony integrity.