Study of cell wall permeability of bacteria from the order Actinomycetales with special emphasis on structure and function of cell wall channels

革兰氏阳性细菌的细胞壁，包括来自放线菌目的细菌，被认为可以自由渗透到小的亲水性溶质。几年前，我们能够证明革兰氏阳性真菌(棒状杆菌亚目或棒状细菌亚目)的两个成员--chelonae分枝杆菌和耻垢分枝杆菌(Trias等人，1992；Benz和Trias，1993；1994)的细胞壁中存在通道，这些细胞壁通道将真菌的菌丝体酸层定义为渗透屏障，并表明它与革兰氏阴性细菌的外膜有某些相似之处。细胞壁通道在真菌生理学中的作用现在被广泛接受。一个仍然悬而未决的问题是，它们在含有非霉菌酸的真菌目近亲中所起的作用。该项目将涉及分枝杆菌细胞壁通道的翻译、结构和组装，重点是对不同棒状杆菌物种的细胞壁通道的研究，如谷氨酸棒杆菌、愈伤棒状杆菌和效率棒状杆菌，它们能够在技术规模上产生氨基酸。特别令人感兴趣的是不同的细胞壁通道蛋白PorA/H/B/C在细胞壁的通透性特性中的作用以及这些蛋白质的突变以改变通道的通透性特性。来自其他革兰氏阳性细菌的细胞壁通道的研究也将继续，这些细菌属于放线菌目。特别令人感兴趣的是不含真菌酸的细菌细胞壁的渗透性的定义，例如来自链霉菌属和棒状杆菌属的细菌，在这里，形成渗透性屏障的脂类的结构应该被阐明和表征。这些细菌的细胞壁通道的初级结构是绝对未知的。通道形成蛋白的基因将被克隆和测序。将尝试使来自不同生物体的细胞壁通道结晶。

The cell walls of gram-positive bacteria including those from the order Actinomycetales were believed to be freely permeable to small hydrophilic solutes. Several years ago we were able to demonstrate the presence of channels in the cell walls of two members of the grampositive mycolata (suborder Corynebacteriaceae or Coryneform bacteria), Mycobactehum chelonae and Mycobacterium smegmatis (Trias et al., 1992; Benz and Trias, 1993; 1994), These cell wall channels define the mycolic acid layer of the mycolata as a permeability barrier and suggest that it shares certain similarities to the outer membrane of gram-negative bacteria. The role of cell wall channels in the physiology of the mycolata is now widely accepted. A still open question is their role in non-mycolic acid containing relatives of mycolata. The project will deal with the translation, structure and assembly of cell wall channels of mycolata with special emphasis on the investigation of those of different Corynebacterium species, such as Corynebacterium glutamicum, Corynebacterium callunae and Corynebacterium efficiens that are able to produce amino acids at a technical scale. Of particular interest is the role of the different cell wall channel proteins PorA/H/B/C in the permeability properties of the cell wall and mutations of the proteins to alter the permeability properties of the channels. The study of the cell wall channels from other gram-positive bacteria, which belong to the order Actinomycetales will also be continued. Of special interest is the definition of the permeability properties of the cell wall of bacteria that that do not contain mycolic acids, such as species from the genera Streptomycetes and Corynebacterium, Here the structure of the lipids that form the permeability barrier should be elucidated and characterized. The primary structure of the cell wall channels of these bacteria is absolutely unknown. The genes of the channel-forming proteins will be cloned and sequenced. Attempts will be made to crystallize cell wall channels from different organisms.