Rowland S L, Katis V L, Partridge S R, Wake R G
Department of Biochemistry, University of Sydney, New South Wales, Australia.
Mol Microbiol. 1997 Jan;23(2):295-302. doi: 10.1046/j.1365-2958.1997.2141580.x.
The Bacillus subtilis cell-division protein DivIB is shown to be present at an approximately 100-fold higher abundance (approximately 5000 molecules per cell) than its Escherichia coli FtsQ homologue. B. subtilis contains much more DivIB (at least 60-fold) than is needed to maintain the normal rate of cell division at moderate temperatures (up to 37 degrees C). However, a high level of DivIB is needed to achieve the normal rate of division at high temperature (47 degrees C). It is proposed that membrane-bound DivIB is involved in stabilizing or promoting the assembly of the division complex (which is intrinsically temperature sensitive) in a manner that requires more of the protein at higher temperatures. The (at least) 60-fold accumulation of DivIB and FtsZ from an undetectable level, following germination and outgrowth of spores up until the stage of the first cell division, was unaffected by blocking of initiation of the first round of replication. It is concluded that there is no major synthesis of either of these 'division initiation' proteins linked to initiation, progression or completion of the first round of replication accompanying spore outgrowth.
已表明枯草芽孢杆菌的细胞分裂蛋白DivIB的丰度比其大肠杆菌FtsQ同源物高约100倍（每个细胞约5000个分子）。在适度温度（高达37摄氏度）下，枯草芽孢杆菌所含的DivIB比维持正常细胞分裂速率所需的量多得多（至少60倍）。然而，在高温（47摄氏度）下需要高水平的DivIB才能实现正常的分裂速率。有人提出，膜结合的DivIB以一种在较高温度下需要更多该蛋白的方式参与稳定或促进分裂复合体（其本质上对温度敏感）的组装。从孢子萌发和生长直至第一次细胞分裂阶段，DivIB和FtsZ从不可检测水平（至少）积累60倍，这不受第一轮复制起始受阻的影响。得出的结论是，在孢子生长过程中，这两种“分裂起始”蛋白的主要合成与第一轮复制的起始、进行或完成没有关联。
