Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, Mexico.
J Bacteriol. 2012 Sep;194(17):4513-20. doi: 10.1128/JB.00460-12. Epub 2012 Jun 15.
Macromolecular structures such as the bacterial flagellum in Gram-negative bacteria must traverse the cell wall. Lytic transglycosylases are capable of enlarging gaps in the peptidoglycan meshwork to allow the efficient assembly of supramolecular complexes. We have previously shown that in Rhodobacter sphaeroides SltF, the flagellar muramidase, and FlgJ, a flagellar scaffold protein, are separate entities that interact in the periplasm. In this study we show that the export of SltF to the periplasm is dependent on the SecA pathway. A deletion analysis of the C-terminal portion of SltF shows that this region is required for SltF-SltF interaction. These C terminus-truncated mutants lose the capacity to interact with themselves and also bind FlgJ with higher affinity than does the wild-type protein. We propose that this region modulates the interaction with the scaffold protein FlgJ during the assembly process.
大分子结构，如革兰氏阴性菌中的细菌鞭毛，必须穿过细胞壁。溶菌转糖苷酶能够扩大肽聚糖网格中的间隙，以允许超分子复合物的有效组装。我们之前已经表明，在球形红杆菌 SltF（鞭毛溶菌酶）和 FlgJ（鞭毛支架蛋白）中，它们是相互作用的独立实体，存在于周质空间中。在这项研究中，我们表明 SltF 向周质空间的输出依赖于 SecA 途径。SltF 的 C 末端部分的缺失分析表明，该区域是 SltF-SltF 相互作用所必需的。这些 C 端截断突变体失去了与自身相互作用的能力，并且与 FlgJ 的结合亲和力也高于野生型蛋白。我们提出，在组装过程中，该区域调节与支架蛋白 FlgJ 的相互作用。
