Nishioka N, Furuno M, Kawagishi I, Homma M
Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya, 464-8602, Japan.
J Biochem. 1998 Jun;123(6):1169-73. doi: 10.1093/oxfordjournals.jbchem.a022057.
Polar flagellum-defective mutants (Pof- Laf-) have been isolated from a lateral flagella-defective mutant (Pof+ Laf-). Among these Pof- Laf- mutants, polar-filamentless mutants, which have the hook structure but not the filament, were identified by electron microscopy. Their hooks were covered with a sheath structure which is contiguous to the outer membrane. The filament proteins, flagellins, were shed into the culture medium of these mutants. These flagellins could be sedimented by high-speed centrifugation even after heat or low pH treatment whereas the depolymerized flagellin of the Pof+ strain was degraded by these treatments. After Triton X-100 treatment, most flagellin of the filamentless mutants could no longer be sedimented, and was degraded. We observed vesicle-like structures on the tips of the hooks and in the flagellin fraction sedimented by high speed centrifugation. These results suggest that flagellin of the filamentless mutants is not assembled into the tip of the hook, but is excreted together with a membrane structure which is probably the sheath of polar flagella.
从侧生鞭毛缺陷型突变体（Pof + Laf -）中分离出了极鞭毛缺陷型突变体（Pof - Laf -）。在这些Pof - Laf -突变体中，通过电子显微镜鉴定出了极丝缺失型突变体，它们具有钩状结构但没有丝状体。它们的钩被一层与外膜相连的鞘状结构覆盖。丝状蛋白鞭毛蛋白被释放到这些突变体的培养基中。即使经过加热或低pH处理，这些鞭毛蛋白仍可通过高速离心沉淀，而Pof +菌株解聚的鞭毛蛋白则会被这些处理降解。用Triton X - 100处理后，大多数无丝状体突变体的鞭毛蛋白不再能沉淀，并被降解。我们在钩的尖端和高速离心沉淀的鞭毛蛋白组分中观察到了囊泡状结构。这些结果表明，无丝状体突变体的鞭毛蛋白没有组装到钩的尖端，而是与一种可能是极鞭毛鞘的膜结构一起被分泌出来。
