Essential Autolysin Activity in Gram-positive Bacteria

描述(申请人提供)：细菌细胞壁是环绕细胞的一种强大的大分子。在过去的十年里，模式生物对参与细胞壁生物合成和重组的蛋白质、酶及其活性已有了普遍的了解。从这些研究中得出的一个主要结论是，细胞壁的维持过程极其复杂，需要许多相关蛋白质的累积相互作用。有人认为细胞壁生物合成机制是以超分子全酶的形式存在的，这一结论是基于大量荧光定位研究的结果，这些研究发现这些酶的亚细胞定位是相互依赖的。尽管取得了许多进展，但对于相关蛋白质的转录反馈环和转录后调控以及对生存的生理重要性仍有许多需要了解。我们对革兰氏阳性细菌基本的WalRK信号转导系统的研究已经确定了这个调控系统，它将细胞生长与随后的细胞壁重组的必要性联系起来。作为这些研究的结果，基本的自溶素活性已被揭示，受到转录和转录后控制，并可能成为先天免疫系统的靶标。基于这一知识，我们建议在这里发现参与枯草杆菌细胞壁动态平衡的许多参与者之间的协同相互作用，作为革兰氏阳性细胞壁维持的模型。细胞壁重组所涉及的蛋白质相互作用的分子和结构细节的鉴定受到这些相互作用的暂时性以及所涉及的蛋白质跨越从细胞质到膜到胞外空间的所有隔室的事实的阻碍。为了确定相互作用的蛋白质之间的相互作用参数，我们最近开发了一种计算方法。该方法依赖于广泛且不断增长的序列数据库，以阐明相互作用的蛋白质之间的接触残基信息。最近的出版物和初步结果强烈支持这一概念，即这项技术通常适用于破译蛋白质相互作用信息，现在将应用于控制细胞壁维持和重组的重要瞬时相互作用的研究。

DESCRIPTION (provided by applicant): The bacterial cell wall is a formidable macromolecule that circumferences the cell. In the past decade a general understanding has been gained for model organisms on the proteins, enzymes and their activities that are involved in the biosynthesis and the restructuring of the cell wall. A main conclusion derived from these studies is that the process of cell wall maintenance is extremely complex and requires the cumulative interactions of many of the involved proteins. It has been suggested that the cell wall biosynthesis machinery exists in the form of a supermolecular holoenzyme, a conclusion that is based on the results from numerous fluorescence localization studies that discovered an interdependence of subcellular localization for these enzymes. Despite these many advances much remains to be learned about the transcriptional feedback loops and posttranscriptional regulations of the involved proteins and the physiologic importance for survival. Our work on the essential WalRK signal transduction system of the Gram-positive bacteria has identified this regulatory system to connect cellular growth with the ensuing necessity for cell wall restructuring. As a consequence of these studies essential autolysin activities have been unveiled that are subject to transcriptional and posttranscriptional control and that might be targeted by the innate immune system. Building on this knowledge we propose here to discover the concerted interplay between the many players that are involved in Bacillus subtilis cell wall homeostasis as a model for Gram-positive cell wall maintenance. The identification of molecular and structural details of the protein interactions involved in cell wall restructuring is hampered y the transient nature of these interactions and by the fact that the involved proteins span all thre compartments of the cell from cytoplasm to membrane to extra-cytoplasmic space. To identify interaction parameters between interacting proteins we recently developed a computational approach. The approach relies on extensive and ever growing sequence databases, to elucidate contact residue information between interacting proteins. Recent publications and preliminary results strongly support the notion that this technology is generally applicable to decipher protein interaction information, and will now be applied to the study of important transient interaction that govern cell wall maintenance and restructuring.