Bramhill D, Thompson C M
Department of Enzymology, Merck Research Laboratories, Rahway, NJ 07065-0900.
Proc Natl Acad Sci U S A. 1994 Jun 21;91(13):5813-7. doi: 10.1073/pnas.91.13.5813.
The FtsZ protein is a GTPase that is essential for cell division in Escherichia coli. During cytokinesis, FtsZ localizes to a ring at the leading edge of septum synthesis. We report the GTP-dependent polymerization of purified FtsZ measured by sedimentation and light scattering. Electron microscopy of polymerized FtsZ revealed structures including tubules 14-20 nm in diameter with longitudinal arrays of protofilaments. FtsZ depolymerized upon removal of GTP and repolymerized after subsequent GTP addition. Mutant FtsZ84 protein polymerized inefficiently, suggesting that polymerization is important for the cellular role of FtsZ in division. The possibility that tubules of FtsZ protein form a cytoskeleton involved in septum synthesis is consistent with our data.
FtsZ蛋白是一种GTP酶，对大肠杆菌的细胞分裂至关重要。在胞质分裂过程中，FtsZ定位于隔膜合成前沿的一个环上。我们报告了通过沉降和光散射测量的纯化FtsZ的GTP依赖性聚合。聚合后的FtsZ的电子显微镜观察显示其结构包括直径为14 - 20纳米的微管，微管中有原丝的纵向排列。去除GTP后FtsZ解聚，随后添加GTP后又重新聚合。突变型FtsZ84蛋白聚合效率低下，这表明聚合对于FtsZ在细胞分裂中的作用很重要。FtsZ蛋白微管形成参与隔膜合成的细胞骨架的可能性与我们的数据一致。
