Center for the Study of Biological Complexity, Virginia Commonwealth University, Richmond, Virginia, USA.
Department of Microbiology and Immunology, Henry Jackson Foundation, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA.
J Biol Chem. 2021 Jan-Jun;296:100700. doi: 10.1016/j.jbc.2021.100700. Epub 2021 Apr 23.
YhcB, a poorly understood protein conserved across gamma-proteobacteria, contains a domain of unknown function (DUF1043) and an N-terminal transmembrane domain. Here, we used an integrated approach including X-ray crystallography, genetics, and molecular biology to investigate the function and structure of YhcB. The Escherichia coli yhcB KO strain does not grow at 45 °C and is hypersensitive to cell wall-acting antibiotics, even in the stationary phase. The deletion of yhcB leads to filamentation, abnormal FtsZ ring formation, and aberrant septum development. The Z-ring is essential for the positioning of the septa and the initiation of cell division. We found that YhcB interacts with proteins of the divisome (e.g., FtsI, FtsQ) and elongasome (e.g., RodZ, RodA). Seven of these interactions are also conserved in Yersinia pestis and/or Vibrio cholerae. Furthermore, we mapped the amino acid residues likely involved in the interactions of YhcB with FtsI and RodZ. The 2.8 Å crystal structure of the cytosolic domain of Haemophilus ducreyi YhcB shows a unique tetrameric α-helical coiled-coil structure likely to be involved in linking the Z-ring to the septal peptidoglycan-synthesizing complexes. In summary, YhcB is a conserved and conditionally essential protein that plays a role in cell division and consequently affects envelope biogenesis. Based on these findings, we propose to rename YhcB to ZapG (Z-ring-associated protein G). This study will serve as a starting point for future studies on this protein family and on how cells transit from exponential to stationary survival.
YhcB 是一种在 γ-变形菌中保守的、功能未知的蛋白（DUF1043 结构域），含有一个 N 端跨膜结构域。在这里，我们使用包括 X 射线晶体学、遗传学和分子生物学在内的综合方法来研究 YhcB 的功能和结构。大肠杆菌 yhcB KO 菌株在 45°C 下无法生长，并且对细胞壁作用的抗生素敏感，即使在静止期也是如此。yhcB 的缺失会导致丝状化、异常 FtsZ 环形成和异常隔膜发育。Z 环对于隔膜的定位和细胞分裂的开始是必不可少的。我们发现 YhcB 与分裂体（例如 FtsI、FtsQ）和伸长体（例如 RodZ、RodA）的蛋白相互作用。这些相互作用中的 7 种在鼠疫耶尔森菌和/或霍乱弧菌中也是保守的。此外，我们还绘制了 YhcB 与 FtsI 和 RodZ 相互作用的氨基酸残基图谱。2.8Å分辨率的杜氏嗜血杆菌 YhcB 胞质结构域的晶体结构显示出一种独特的四聚体 α-螺旋卷曲螺旋结构，可能参与将 Z 环与隔膜肽聚糖合成复合物连接起来。总之，YhcB 是一种保守的、条件必需的蛋白，在细胞分裂中发挥作用，进而影响包膜生物发生。基于这些发现，我们建议将 YhcB 重新命名为 ZapG（Z 环相关蛋白 G）。这项研究将为该蛋白家族以及细胞如何从指数生长期过渡到静止期生存的未来研究提供一个起点。
