Jackson Shelley N, Wang Hay-Yan J, Woods Amina S
NIDA IRP, National Institutes of Health, Baltimore, Maryland 21224, USA.
J Proteome Res. 2005 Nov-Dec;4(6):2360-3. doi: 10.1021/pr050261d.
Our previous work has highlighted the role of certain amino acid residues, mainly two or more adjacent arginine on one peptide and two or more adjacent glutamate, or aspartate, or a phosphorylated residue on the other in the formation of noncovalent complexes (NCX) between peptides. In the present study, we employ ESI-MS to investigate the gas-phase stability and dissociation pathways of the NCX of a basic peptide VLRRRRKRVN, an epitope from the third intracellular loop of the dopamine D(2) receptor, with the phosphopetide SVSTDpTpSAE, an epitope from the cannabinoid CB1 carboxyl terminus. ESI-MS/MS analysis of the NCX between VLRRRRKRVN and SVSTDpTpSAE suggests two dissociation pathways for the NCX. The major pathway is the disruption of the electrostatic interactions between the Arg residues and the phosphate groups, while an alternative pathway is also recorded, in which the complex is dissociated along the covalent bond between the oxygen from either Thr or Ser and HPO(3). To verify the alternative pathway, we have used an ion trap instrument to conduct MS(3) analysis on the product ions of both dissociation pathways.
我们之前的工作强调了某些氨基酸残基的作用，主要是一条肽链上两个或更多相邻的精氨酸以及另一条肽链上两个或更多相邻的谷氨酸、天冬氨酸或一个磷酸化残基在肽之间形成非共价复合物（NCX）中的作用。在本研究中，我们采用电喷雾电离质谱（ESI-MS）来研究碱性肽VLRRRRKRVN（多巴胺D(2)受体第三个细胞内环的一个表位）与磷酸肽SVSTDpTpSAE（大麻素CB1羧基末端的一个表位）形成的NCX在气相中的稳定性和解离途径。对VLRRRRKRVN与SVSTDpTpSAE之间的NCX进行ESI-MS/MS分析表明该NCX有两条解离途径。主要途径是精氨酸残基与磷酸基团之间的静电相互作用被破坏，同时还记录到另一条途径，即复合物沿着苏氨酸或丝氨酸的氧与HPO(3)之间的共价键解离。为了验证这条替代途径，我们使用离子阱仪器对两条解离途径的产物离子进行了串联质谱（MS(3)）分析。
