Matthews B W, Remington S J
Proc Natl Acad Sci U S A. 1974 Oct;71(10):4178-82. doi: 10.1073/pnas.71.10.4178.
The three dimensional structure of the lysozyme from bacteriophage T4 has been determined from a 2.5 A resolution electron density map. About 60% of the molecule is in a helical conformation and there is one region consisting of antiparallel beta-structure. The polypeptide backbone folds into two distinct lobes linked in part by a long helix. In the region between the two lobes, there is a cleft which deepens into a hole or cavity, about 6-8 A in diameter, extending from one side of the molecule to the other. This opening is closed off by side chains which extend to within 3-5 A of each other. A number of mutant lysozymes in which residues in the vicinity of the opening are modified have markedly reduced catalytic activity, suggesting that this region of the molecule may be catalytically important. The three dimensional structure of T4 phage lysozyme is quite different from that of hen egg-white lysozyme although it is not clear at this time whether or not the mechanisms of catalysis of the respective enzymes are related.
已从分辨率为2.5埃的电子密度图确定了噬菌体T4溶菌酶的三维结构。该分子约60%呈螺旋构象,有一个区域由反平行β结构组成。多肽主链折叠成两个不同的叶,部分由一个长螺旋连接。在两个叶之间的区域,有一个裂缝,该裂缝加深形成一个直径约6 - 8埃的孔或腔,从分子的一侧延伸到另一侧。这个开口被相互延伸至彼此3 - 5埃范围内的侧链封闭。许多在开口附近残基被修饰的突变溶菌酶催化活性显著降低,这表明分子的这个区域可能在催化方面很重要。噬菌体T4溶菌酶的三维结构与鸡蛋清溶菌酶的三维结构有很大不同,尽管目前尚不清楚各自酶的催化机制是否相关。