EMBL Hamburg Outstation, c/o DESY, Notkestrasse 85, D22603, Hamburg, Germany.
Structure. 2011 Jan 12;19(1):56-69. doi: 10.1016/j.str.2010.11.010.
The open reading frame rv1364c of Mycobacterium tuberculosis, which regulates the stress-dependent σ factor, σ(F), has been analyzed structurally and functionally. Rv1364c contains domains with sequence similarity to the RsbP/RsbW/RsbV regulatory system of the stress-response σ factor of Bacillus subtilis. Rv1364c contains, sequentially, a PAS domain (which shows sequence similarity to the PAS domain of the B. subtilis RsbP protein), an active phosphatase domain, a kinase (anti-σ(F) like) domain and a C-terminal anti-σ(F) antagonist like domain. The crystal structures of two PAS domain constructs (at 2.3 and 1.6 Å) and a phosphatase/kinase dual domain construct (at 2.6 Å) are described. The PAS domain is shown to bind palmitic acid but to have 100 times greater affinity for palmitoleic acid. The full-length protein can exist in solution as both monomer and dimer. We speculate that a switch between monomer and dimer, possibly resulting from fatty acid binding, affects the accessibility of the serine of the C-terminal, anti-σ(F) antagonist domain for dephosphorylation by the phosphatase domain thus indirectly altering the availability of σ(F).
结核分枝杆菌 rv1364c 的开放阅读框，它调节应激相关 σ 因子 σ(F)，已在结构和功能上进行了分析。Rv1364c 包含与枯草芽孢杆菌应激响应 σ 因子的 RsbP/RsbW/RsbV 调节系统具有序列相似性的结构域。Rv1364c 依次包含 PAS 结构域（与枯草芽孢杆菌 RsbP 蛋白的 PAS 结构域具有序列相似性）、活性磷酸酶结构域、激酶（抗-σ(F) 样）结构域和 C 末端抗-σ(F)拮抗剂样结构域。描述了两个 PAS 结构域构建体（分别为 2.3 和 1.6Å）和一个磷酸酶/激酶双结构域构建体（2.6Å）的晶体结构。结果表明，PAS 结构域可以结合棕榈酸，但对棕榈油酸的亲和力要高出 100 倍。全长蛋白可以在溶液中以单体和二聚体形式存在。我们推测单体和二聚体之间的转换，可能是由于脂肪酸结合引起的，会影响 C 末端抗-σ(F)拮抗剂结构域丝氨酸的可及性，从而使磷酸酶结构域去磷酸化，从而间接改变 σ(F)的可用性。
