Institute of Biostructures and Bioimaging, CNR, Via Mezzocannone 16, I-80134, Napoli, Italy.
Biochem J. 2011 Apr 1;435(1):33-41. doi: 10.1042/BJ20101643.
Bacterial serine/threonine kinases modulate a wide number of cellular processes. The serine/threonine kinase PrkC from the human pathogen Staphylococcus aureus was also shown to induce germination of Bacillus subtilis spores, in response to cell wall muropeptides. The presence of muropeptides in the bacterial extracellular milieu is a strong signal that the growing conditions are promising. In the present paper, we report the X-ray structure of the entire extracellular region of PrkC from S. aureus. This structure reveals that the extracellular region of PrkC, EC-PrkC, is a linear modular structure composed of three PASTA (penicillin binding-associated and serine/threonine kinase-associated) domains and an unpredicted C-terminal domain, which presents the typical features of adhesive proteins. Using several solution techniques, we also found that EC-PrkC shows no tendency to dimerize even in the presence of high concentrations of muropeptides. X-ray structural results obtained in the present study provide molecular clues into the mechanism of muropeptide-induced PrkC activation.
细菌丝氨酸/苏氨酸激酶调节许多细胞过程。来自人类病原体金黄色葡萄球菌的丝氨酸/苏氨酸激酶 PrkC 也被证明能够响应细胞壁肽聚糖诱导枯草芽孢杆菌孢子的萌发。肽聚糖存在于细菌细胞外环境中是一个强烈的信号，表明生长条件是有利的。在本文中，我们报告了来自金黄色葡萄球菌的 PrkC 的整个细胞外区域的 X 射线结构。该结构表明，PrkC 的细胞外区域 EC-PrkC 是由三个 PASTA（青霉素结合相关和丝氨酸/苏氨酸激酶相关）结构域和一个未预测的 C 末端结构域组成的线性模块化结构，该结构域呈现出典型的粘附蛋白特征。使用几种溶液技术，我们还发现，即使在高浓度肽聚糖存在的情况下，EC-PrkC 也没有二聚化的趋势。本研究中获得的 X 射线结构结果为肽聚糖诱导 PrkC 激活的机制提供了分子线索。
