Inactivation of swmA results in the loss of an outer cell layer in a swimming Synechococcus strain
Inactivation of swmA results in the loss of an outer cell layer in a swimming Synechococcus strain
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DOI：
10.1128/jb.187.1.224-230.2005
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发表时间：
2005-01-01
影响因子：
3.2
通讯作者：
Brahamsha, B
中科院分区：
文献类型：
--
作者：
McCarren, J;Heuser, J;Brahamsha, B
海洋单细胞蓝藻的非鞭毛游泳机制尚不清楚。SwmA是一种丰富的细胞表面相关的130 kda糖蛋白，是聚球菌属菌株WH8102产生推力所必需的。野生型细胞与插入失活SwmA基因的突变株的超微结构比较显示，突变株在外膜外缺乏一层。冷冻固定和冷冻替代是保存这一外层的必要条件。冻裂和蚀刻表明，这一附加层是s层。s层如何在运动中发挥作用仍然难以捉摸；然而，这项工作描述了这种独特类型的游泳所需的超微结构成分。此外，这里提出的工作描述了一个模型游泳蓝藻的包膜结构。
The mechanism of nonflagellar swimming of marine unicellular cyanobacteria remains poorly understood. SwmA is an abundant cell surface-associated 130-kDa glycoprotein that is required for the generation of thrust in Synechococcus sp. strain WH8102. Ultrastructural comparisons of wild-type cells to a mutant strain in which the gene encoding SwmA has been insertionally inactivated reveal that the mutant lacks a layer external to the outer membrane. Cryofixation and freeze-substitution are required for the preservation of this external layer. Freeze fracturing and etching reveal that this additional layer is an S-layer. How the S-layer might function in motility remains elusive; however, this work describes an ultrastructural component required for this unique type of swimming. In addition, the work presented here describes the envelope structure of a model swimming cyanobacterium.