Daniel R A, Harry E J, Errington J
Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK.
Mol Microbiol. 2000 Jan;35(2):299-311. doi: 10.1046/j.1365-2958.2000.01724.x.
We have characterized the role of the penicillin-binding protein PBP 2B in cell division of Bacillus subtilis. We have shown that depletion of the protein results in an arrest in division, but that this arrest is slow, probably because the protein is relatively stable. PBP 2B-depleted filaments contained, at about their mid-points, structures resembling partially formed septa, into which most, if not all, of the division proteins had assembled. Although clearly deficient in wall material, membrane invagination seemed to continue, indicating that membrane and wall ingrowth can be uncoupled. At other potential division sites along the filaments, no visible ingrowths were observed, although FtsZ rings assembled at regular intervals. Thus, PBP 2B is apparently required for both the initiation of division and continued septal ingrowth. Immunofluorescence microscopy showed that the protein is recruited to the division site. The pattern of localization suggested that this recruitment occurs continually during septal ingrowth. During sporulation, PBP 2B was present transiently in the asymmetrical septum of sporulating cells, and its availability may play a role in the regulation of sporulation septation.
我们已经阐明了青霉素结合蛋白PBP 2B在枯草芽孢杆菌细胞分裂中的作用。我们发现该蛋白的缺失会导致细胞分裂停滞，但这种停滞过程较为缓慢，可能是因为该蛋白相对稳定。PBP 2B缺失的丝状菌体在其大约中点位置含有类似部分形成的隔膜的结构，大多数（如果不是全部）分裂蛋白已组装到其中。尽管明显缺乏细胞壁物质，但膜内陷似乎仍在继续，这表明膜和细胞壁的向内生长可能是解偶联的。在沿着丝状菌体的其他潜在分裂位点，尽管FtsZ环有规律地组装，但未观察到明显的向内生长。因此，PBP 2B显然对于分裂的起始和隔膜的持续向内生长都是必需的。免疫荧光显微镜检查表明该蛋白被募集到分裂位点。定位模式表明这种募集在隔膜向内生长过程中持续发生。在芽孢形成过程中，PBP 2B短暂存在于芽孢形成细胞的不对称隔膜中，其可用性可能在芽孢形成隔膜的调节中起作用。
