Cendrowicz Ewa, de Sousa Borges Anabela, Kopacz Malgorzata, Scheffers Dirk-Jan
Department of Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, the Netherlands.
PLoS One. 2017 Mar 30;12(3):e0174713. doi: 10.1371/journal.pone.0174713. eCollection 2017.
SpoIIE is a bifunctional protein involved in asymmetric septum formation and in activation of the forespore compartment-specific transcription factor σF through dephosphorylation of SpoIIAA-P. The phosphatase activity of SpoIIE requires Mn2+ as a metal cofactor. Here, we show that the presence of a metal cofactor also influences SpoIIE oligomerization and asymmetric septum formation. Absence of Mn2+ from sporulation medium results in a delay of the formation of polar FtsZ-rings, similar to a spoIIE null mutant. We purified the entire cytoplasmic part of the SpoIIE protein, and show that the protein copurifies with bound metals. Metal binding both stimulates SpoIIE oligomerization, and results in the formation of larger oligomeric structures. The presence of SpoIIE oligomers reduces FtsZ GTP hydrolysis activity and stabilizes FtsZ polymers in a light scattering assay. Combined, these results indicate that metal binding is not just required for SpoIIE phosphatase activity but also is important for SpoIIE's role in asymmetric septum formation.
SpoIIE是一种双功能蛋白,参与不对称隔膜的形成,并通过使SpoIIAA-P去磷酸化来激活前芽孢区室特异性转录因子σF。SpoIIE的磷酸酶活性需要Mn2+作为金属辅因子。在此,我们表明金属辅因子的存在也会影响SpoIIE的寡聚化和不对称隔膜的形成。芽孢形成培养基中缺乏Mn2+会导致极性FtsZ环形成延迟,类似于spoIIE基因敲除突变体。我们纯化了SpoIIE蛋白的整个细胞质部分,并表明该蛋白与结合的金属一起共纯化。金属结合既刺激SpoIIE的寡聚化,又导致形成更大的寡聚结构。在光散射实验中,SpoIIE寡聚物的存在降低了FtsZ的GTP水解活性并稳定了FtsZ聚合物。综合这些结果表明,金属结合不仅是SpoIIE磷酸酶活性所必需的,而且对SpoIIE在不对称隔膜形成中的作用也很重要。