Lupas A, Engelhardt H, Peters J, Santarius U, Volker S, Baumeister W
Max-Planck-Institut für Biochemie, Martinsried, Germany.
J Bacteriol. 1994 Mar;176(5):1224-33. doi: 10.1128/jb.176.5.1224-1233.1994.
The three-dimensional structure of the Acetogenium kivui surface layer (S-layer) has been determined to a resolution of 1.7 nm by electron crystallographic techniques. Two independent reconstructions were made from layers negatively stained with uranyl acetate and Na-phosphotungstate. The S-layer has p6 symmetry with a center-to-center spacing of approximately 19 nm. Within the layer, six monomers combine to form a ring-shaped core surrounded by a fenestrated rim and six spokes that point towards the axis of threefold symmetry and provide lateral connectivity to other hexamers in the layer. The structure of the A. kivui S-layer protein is very similar to that of the Bacillus brevis middle wall protein, with which it shares an N-terminal domain of homology. This domain is found in several other extracellular proteins, including the S-layer proteins from Bacillus sphaericus and Thermus thermophilus, Omp alpha from Thermotoga maritima, an alkaline cellulase from Bacillus strain KSM-635, and xylanases from Clostridium thermocellum and Thermoanaerobacter saccharolyticum, and may serve to anchor these proteins to the peptidoglycan. To our knowledge, this is the first example of a domain conserved in several S-layer proteins.
通过电子晶体学技术，已确定了基维产乙酸菌表面层（S层）的三维结构，分辨率达到1.7纳米。从用醋酸铀酰和磷酸钨钠负染色的层中进行了两次独立的重建。S层具有p6对称性，中心间距约为19纳米。在该层内，六个单体结合形成一个环形核心，周围是有孔的边缘和六个指向三重对称轴并为该层中其他六聚体提供横向连接的辐条。基维产乙酸菌S层蛋白的结构与短短芽孢杆菌中壁蛋白的结构非常相似，它们共享一个同源的N端结构域。该结构域存在于其他几种细胞外蛋白中，包括球形芽孢杆菌和嗜热栖热菌的S层蛋白、海栖热袍菌的Ompα、芽孢杆菌菌株KSM - 635的碱性纤维素酶以及热纤梭菌和嗜糖嗜热栖热菌的木聚糖酶，并且可能用于将这些蛋白锚定到肽聚糖上。据我们所知，这是在几种S层蛋白中保守的结构域的首个实例。
