Pfeffer S, Höhne W, Branner S, Wilson K, Betzel C
European Molecular Biology Laboratory, Hamburg, Germany.
FEBS Lett. 1991 Jul 8;285(1):115-9. doi: 10.1016/0014-5793(91)80738-o.
Bacitracins are a group of widely used peptide antibiotics. There has been interest in determining the three-dimensional structure of the bacitracins. However, solution studies indicate significant flexibility in their structure and to date native bacitracins have resisted attempts at crystallisation despite considerable efforts over a number of years by several groups. Here we report the first three-dimensional X-ray structure of a bacitracin, complexed to a subtilisin proteinase. X-Ray diffraction data were collected using synchrotron radiation in combination with the Image Plate Scanner system. The complex structure including two enzymes, two bacitracins, 220 water molecules and two Ca2+ ions was refined by restrained least-squares to a crystallographic R factor ( = sigma [[Fo-Fc]]/sigma [Fo]]) of 16.3% at 2.0 A.
杆菌肽是一类广泛使用的肽抗生素。人们一直对确定杆菌肽的三维结构感兴趣。然而，溶液研究表明其结构具有显著的灵活性，并且尽管多个研究小组多年来付出了相当大的努力，但迄今为止天然杆菌肽仍难以结晶。在此我们报告了首个与枯草杆菌蛋白酶复合的杆菌肽的三维X射线结构。使用同步辐射结合成像板扫描仪系统收集了X射线衍射数据。该复合结构包括两种酶、两个杆菌肽、220个水分子和两个Ca2+离子，通过约束最小二乘法精修至在2.0 Å分辨率下晶体学R因子（= sigma [[Fo-Fc]]/sigma [Fo]）为16.3%。
