Tang X J, Brewer C F, Saha S, Chernushevich I, Ens W, Standing K G
Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York 10461.
Rapid Commun Mass Spectrom. 1994 Sep;8(9):750-4. doi: 10.1002/rcm.1290080918.
Noncovalent interactions in soybean agglutinin (SBA) were studied on an electrospray ionization (ESI) time-of-flight mass spectrometer constructed recently at the University of Manitoba. The high m/z range and high sensitivity of the instrument together with mild ESI interface conditions turned out to be ideal for detecting this noncovalently bonded tetrameric protein (MW approximately 116,000 Da) in low charge states (z = 23 to 27). By altering the acetonitrile content of the SBA solutions it was shown that the observed SBA tetramers are due to structurally specific noncovalent associations in solution. Octamers and dodecamers (MW approximately 350,000 Da) were also detected. Information on the quaternary structure of the tetramers was obtained by analyzing the fragment-ion spectrum resulting from the collision-induced dissociation of the tetramer ions.
利用曼尼托巴大学最近构建的电喷雾电离（ESI）飞行时间质谱仪，对大豆凝集素（SBA）中的非共价相互作用进行了研究。该仪器的高m/z范围、高灵敏度以及温和的ESI接口条件，对于检测处于低电荷态（z = 23至27）的这种非共价结合的四聚体蛋白（分子量约116,000 Da）而言，结果证明是理想的。通过改变SBA溶液中的乙腈含量表明，观察到的SBA四聚体是由于溶液中结构特异性的非共价缔合所致。还检测到了八聚体和十二聚体（分子量约350,000 Da）。通过分析四聚体离子碰撞诱导解离产生的碎片离子谱，获得了有关四聚体四级结构的信息。
