PDF(Pubmed)
Abstract：
FtsZ is highly conserved among bacteria and plays an essential role in bacterial cell division. The tense conformation of FtsZ bound to GTP assembles into a straight filament via head-to-tail associations, and then the upper subunit of FtsZ hydrolyzes GTP bound to the lower FtsZ subunit. The subunit with GDP bound disassembles accompanied by a conformational change in the subunit from the tense to relaxed conformation. Although crystal structures of FtsZ derived from several bacterial species have been determined, the conformational change from the relaxed to tense conformation has only been observed in Staphylococcus aureus FtsZ (SaFtsZ). Recent cryo-electron microscopy analyses revealed the three-dimensional reconstruction of the protofilament, in which tense molecules assemble via head-to-tail associations. However, the lower resolution of the protofilament suggested that the flexibility of the FtsZ protomers between the relaxed and tense conformations caused them to form in less-strict alignments. Furthermore, this flexibility may also prevent FtsZs other than SaFtsZ from crystalizing in the tense conformation, suggesting that the flexibility of bacterial FtsZs differs. In this study, molecular dynamics simulations were performed using SaFtsZ and Bacillus subtilis FtsZ in several situations, which suggested that different features of the FtsZs affect their conformational stability.
摘要：
FtsZ在细菌中高度保守，在细菌细胞分裂中起重要作用。与GTP结合的FtsZ的紧张构象通过头对尾关联组装成直丝，然后FtsZ的上部亚基水解与下部FtsZ亚基结合的GTP。具有GDP结合的亚基分解，并伴随着亚基从时态到松弛构象的构象变化。尽管已经确定了来自几种细菌物种的FtsZ的晶体结构，仅在金黄色葡萄球菌FtsZ（SaFtsZ）中观察到从放松到紧张构象的构象变化。最近的低温电子显微镜分析显示了原丝的三维重建，其中紧张分子通过头对尾关联组装。然而,原丝的分辨率较低，表明FtsZ原丝在放松和紧张构象之间的灵活性导致它们以不太严格的排列形式形成。此外，这种灵活性也可以防止SaFtsZ以外的FtsZ在紧张构象中结晶，这表明细菌FtsZ的灵活性不同。在这项研究中,在几种情况下，使用SaFtsZ和枯草芽孢杆菌FtsZ进行了分子动力学模拟，这表明FtsZ的不同特征影响其构象稳定性。
