Distance calculation of residues neighbouring to lysozyme antigenic sites. Site-neighbouring residues whose evolutionary substitution can modify the characteristics and binding energy of the sites.
Distance calculation of residues neighbouring to lysozyme antigenic sites. Site-neighbouring residues whose evolutionary substitution can modify the characteristics and binding energy of the sites.
复制标题
与溶菌酶抗原位点相邻的残基的距离计算。
作者：
M. Atassi;A. Kazim
通过使用本实验室确定的溶菌酶的抗原结构和X射线坐标，我们计算了三个抗原位点中的每个残基与溶菌酶分子的所有其他氨基酸之间的最近原子距离。这些计算使我们能够识别每个位点残基的最近邻居。因此描述了每个位点残基的直接环境。对于三个抗原位点，共有 71 个相邻残基。讨论了位点邻近残基中的进化氨基酸取代对蛋白质结合位点的结合能力的影响，特别是对蛋白质抗原位点的影响。这些，连同位点残留物的直接替换，将产生主要影响。然而，这种治疗方法的局限性受到强调。一旦去除，甚至在更远的位置，替换对抗原位点的影响较小，当这些影响累积时，可能会相当大，以及由于进化氨基酸替换而可能发生的构象重新调整的任何影响，引起了人们的注意。
By using the antigenic structure of lysozyme determined in this laboratory and the X-ray co-ordinates we have calculated the closest-atom distances between each of the residues in the three antigenic sites and all the other amino acids of the lysozyme molecule. These calculations enabled us to identify the nearest neighbours to each of the site residues. Thus the immediate environment of each site residue is described. For the three antigenic sites there is a total of 71 neighbouring residues. The effects of evolutionary amino acid substitutions in site-neighbouring residues on the binding capacity of protein binding sites in general and on protein antigenic sites in particular are discussed. These, together with the direct replacements in site residues, will acount for the major effects. However, the limitations of this treatment are stressed. The smaller effects on antigenic sites of replacements at once-removed and even at more distant locations, which, when they become cumulative, could be considerable, are brought to attention, together with any influences of conformational readjustments that can take place as a result of evolutionary amino acid replacements.