Reversible Hydrogen Transfer between Cysteine Thiyl Radical and Glycine and Alanine in Model Peptides: Covalent H/D Exchange, Radical−Radical Reactions, and <scp>l</scp>- to <scp>d</scp>-Ala Conversion
作者:Olivier Mozziconacci、Bruce A. Kerwin、Christian Schöneich
DOI:10.1021/jp101508b
日期:2010.5.20
The reversible intramolecular hydrogen transfer reaction of peptide Cys thiyl radicals with Gly and Ala residues was studied in model peptides, where thiyl radicals were either generated through photochemical cleavage of disulfide bonds or through the reaction of Cys thiol with •CH3 or CH3C•O radicals, or both, generated through photolysis of acetone. In D2O, the reversible hydrogen transfer leads
在模型肽中研究了肽Cys巯基与Gly和Ala残基的可逆分子内氢转移反应,其中巯基通过二硫键的光化学裂解或Cys硫醇与• CH 3或CH 3 C反应生成•丙酮光解产生的O自由基,或两者兼而有之。在D 2 O中,可逆的氢转移导致共价H / D交换,表明中间碳中心自由基的位置。另外,可逆形成的α Ç •上丙氨酸引线自由基的转化升-Ala到d-Ala,其中这种转化的效率取决于含Ala肽的一级序列。当Cys巯基与• CH 3或CH 3 C • O自由基反应生成Cys硫基自由基时,这些起始自由基与肽硫代巯基和以碳为中心的自由基之间的各种重组产物可提供进一步证据,证明中间体自由基在碳氢化合物中的位置。肽序列。