The influence of histidine on cleavage C-terminal to acidic residues in doubly protonated tryptic peptides
The influence of histidine on cleavage C-terminal to acidic residues in doubly protonated tryptic peptides
复制标题
DOI：
10.1016/s1387-3806(02)00660-7
复制
发表时间：
2002-08-01
影响因子：
1.8
通讯作者：
Yates, JR
中科院分区：
文献类型：
--
作者：
Huang, YY;Wysocki, VH;Yates, JR
利用505个双质子化胰蛋白酶多肽的离子阱CID MS/MS谱数据库，研究了内部碱性残基对酸性氨基酸残基天冬氨酸（Asp）和谷氨酸（Glu）C-末端优先裂解的影响。由于选择含有C-末端Lys或Arg的胰蛋白酶肽进行分析，因此大多数肽含有His作为内部碱性残基。比较含有和不含有内部碱性残基的肽的光谱表明，对于含有内部碱性残基的肽，Asp-Xxx键处的裂解更突出。这一结果证实了先前发表的Asp-Xxx裂解机制，即当质子被螯合在碱性位点时，Asp-Xxx的裂解增强，从而允许Asp侧链的酸性氢启动裂解。这些数据表明，在双电荷的His-含有胰蛋白酶肽，一个质子通常位于C-末端的精氨酸或赖氨酸，而第二个质子的流动性是由His侧链的相对较高的碱度阻碍。对Glu-Xxx酰胺键处的裂解进行了相同的研究，但在这种情况下，含有和不含有内部碱性残基的肽之间仅存在微小差异。(C)2002 Elsevier Science B. V.保留所有权利。
An ion-trap CID MS/MS spectral database of 505 doubly protonated tryptic peptides was used to investigate the influence of an internal basic residue on preferential fragmentation C-terminal to the acidic amino acid residues, aspartic acid (Asp) and glutamic acid (Glu). Because tryptic peptides, which contain C-terminal Lys or Arg, were selected for analysis, the majority of the peptides contain His as the internal basic residue. A comparison between spectra for peptides that do and do not contain an internal basic residue shows that cleavage is more prominent at Asp-Xxx bonds for peptides that do contain the internal basic residue. This result corroborates a previously published mechanism for Asp-Xxx cleavage that states that cleavage at Asp-Xxx is enhanced when protons are sequestered at basic sites, allowing the acidic hydrogen of the Asp side chain to initiate cleavage. The data suggest that in doubly-charged His-containing tryptic peptides, one proton is typically located at the C-terminal Arg or Lys while the mobility of the second proton is hindered by the His side chain's relatively high basicity. The same investigation was performed for cleavage at Glu-Xxx amide bonds, but in this case there is only a marginal difference between peptides that do and do not contain the internal basic residue. (C) 2002 Elsevier Science B.V. All rights reserved.