Cascade dissociations of peptide cation-radicals. Part 1. Scope and effects of amino acid residues in penta-, nona-, and decapeptides.
Cascade dissociations of peptide cation-radicals. Part 1. Scope and effects of amino acid residues in penta-, nona-, and decapeptides.
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DOI：
10.1007/s13361-012-0408-9
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发表时间：
2012-08
影响因子：
3.2
通讯作者：
Turecek, Frantisek
中科院分区：
文献类型：
--
作者：
Chung, Thomas W.;Hui, Renjie;Ledvina, Aaron;Coon, Joshua J.;Turecek, Frantisek
氨基酸残基特异性的骨架和侧链解离的肽z离子在MS 3光谱中阐明了超过40个五肽与精氨酸C-终止序列的AAXAR和AAHXR型，九肽的AAHAAXYAR和AAHAXAYAR型，和AAHAAXYAAR十肽。含有具有易于转移的苄基或叔β-氢原子（Phe、Tyr、His、Trp、瓦尔）的氨基酸残基的肽Zn离子经历容易的主链裂解以形成主要的Zn-2或Zn-3离子。这些骨架裂解被认为是由侧链β-氢原子转移到z离子Cα自由基位点，随后相邻Cα-CO键均裂解离，形成zn-2 + HNCO阳离子自由基，其通过失去HNCO而自发解离。不具有易转移的β-氢原子的氨基酸残基（Gly、Ala）不经历zn → zn-2解离。在含有Asp和Asn残基的z离子中，主链裂解与侧链解离竞争。侧链解离被认为是由α-氢原子转移引发的，该转移激活Cβ-Cγ或Cβ-杂原子键，以解离，该解离支配来自含有Leu、Cys、Lys、Met、Ser、Arg、Glu和Gln残基的肽的z离子的MS 3光谱。Lys、Arg、Gln和Glu残基也参与γ-氢原子转移，从而引发其他侧链解离。
Amino acid residue-specific backbone and side-chain dissociations of peptide z ions in MS3 spectra were elucidated for over 40 pentapeptides with arginine C-terminated sequences of the AAXAR and AAHXR type, nonapeptides of the AAHAAXYAR and AAHAXAYAR type, and AAHAAXYAAR decapeptides. Peptide zn ions containing amino acid residues with readily transferrable benzylic or tertiary β-hydrogen atoms (Phe, Tyr, His, Trp, Val) underwent facile backbone cleavages to form dominant zn-2 or zn-3 ions. These backbone cleavages are thought to be triggered by a side-chain β-hydrogen atom transfer to the z ion Cα radical site followed by homolytic dissociation of the adjacent Cα—CO bond, forming zn-2 + HNCO cation-radicals that spontaneously dissociate by loss of HNCO. Amino acid residues that do not have readily transferrable β-hydrogen atoms (Gly, Ala) do not undergo the zn → zn-2 dissociations. The backbone cleavages compete with side-chain dissociations in z ions containing Asp and Asn residues. Side-chain dissociations are thought to be triggered by α-hydrogen atom transfers that activate the Cβ—Cγ or Cβ—heteroatom bonds for dissociations that dominate the MS3 spectra of z ions from peptides containing Leu, Cys, Lys, Met, Ser, Arg, Glu and Gln residues. The Lys, Arg, Gln, and Glu residues also participate in γ-hydrogen atom transfers that trigger other side-chain dissociations.
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影响因子：
1.8
作者：
Moran, Damian;Jacob, Rebecca;Radom, Leo
通讯作者：
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Turecek, Frantisek
影响因子：
3.3
作者：
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通讯作者：
Turecek, Frantisek