ATP与氨基酸弱相互作用的质谱与理论计算研究

摘要

利用电喷雾质谱、荧光、核磁和理论计算研究了ATP与19种氨基酸的弱相互作用.在质谱中发现除甘氨酸(Gly)、丙氨酸(Ala)、缬氨酸(Val)外,其它氨基酸均可观测到与ATP因弱相互作用形成的复合物离子.利用不同质谱锥孔电压下复合物稳定性的不同,分析了侧链基团对ATP与19种氨基酸弱相互作用的影响.并利用荧光光谱和核磁共振波谱法研究了芳香性氨基酸与ATP的弱相互作用.结果表明,氨基酸与ATP的弱相互作用强弱顺序为:色氨酸(Trp)＞苯丙氨酸(Phe)＞具有R‖C-NH2的氨基酸＞具有-RCOOH、-R-NH2的氨基酸＞具有-RSH、-ROH的氨基酸＞R为长链的氨基酸＞R为短链的氨基酸.不同官能团的氨基酸与ATP的弱相互作用的模拟计算也证实了此结论,并发现氨基酸的主侧链基团与ATP分子基团间的多个分子间因氢键作用使复合物能稳定存在.这一结果将为预测蛋白与ATP结合位点及研究ATP的识别机理提供依据.%The non-covalent interactions between adenosine 5′-triphosphate(ATP) and 19 kinds of amino acids(AA) were investigated by electrospray ionization tandem mass spectrometry(ESI MS/MS),fluorescence spectrometry,nuclear magnetic resonance(NMR) and theoretical calculation.The non-covalent complexes of ATP and AA were observed except those of ATP and Gly,Ala,Val in mass spectra.The influence of the group on the side chain of amino acids on the non-covalent interactions was analyzed by comparing the stability of the complexes through tuning cone voltage of the spectrometry.The non-covalent interactions between ATP and Phe or Trp were also investigated by fluorescence spectrometry and NMR.The affinity sequence of AA for ATP was obtained as follows:Trp＞Phe＞ amino acids with R‖C-NH2 on the side chain ＞ amino acids with -RCOOH,-R-NH2 on the side chain＞amino acids with -RSH,-ROH on the side chain＞amino acids with long alkyl substituent ＞ amino acids with short alkyl substituent.The result of theoretical calculation was consistent favorably with that of experimental conclusion except Phe.By theoretical calculation,the intermolecular hydrogen bonds were confirmed to stabilize the non-covalent complexes.The non-covalent interactions between ATP and the groups of amino acids play an important role on the molecule recognition of ATP by proteins.The conclusion will throw light on the prediction of ATP binding site and study of molecule recognition mechanism of ATP.