MALDI方法研究蛋白质的非共价复合物

飞行时间质谱仪(TOFMS)在理论上无质量范围的限制,可实现大分子蛋白质与核酸的非共价复合物的直接检测.特别是在近中性溶液条件下通过对芥子酸和6-氮杂-2-硫代胸腺嘧啶基质的使用及双层样品制备方法的改善,获得了稳定复合物的高灵敏度质谱检测.肌红蛋白-血红素复合物能够在芥子酸基质的不同pH条件下(pH2.0或pH5.0)同时观察到.而运用双层样品制备方法,获得了核糖核酸酶复合物(RNaseS)在第一次激光照射下的突出质谱峰,但其丰度均随更多的激光打击而减弱.

Studies of Non-covalent Protein Complexes by MALDI Methods

Several specific noncovalent protein complexes were successfully observed by matrix assisted desorption ionization mass spectrometry(MALDI MS). The methods described in this paper include the matrixes use of sinapinic acid(SA) and 6aza2thiothymine(ATT) in neutral pH solution, as well as the improvement of twolayer sample preparation method to achieve a high sensitivity detection of stable noncovalent complexes. Myoglobinheme complex was found simultaneously with the sinapinic acid matrix in the various pH solution(pH=2 or pH=5). The RNase S complex showed a striking intensity at the first shot, which was decreased with more laser shots. Most importantly, the observation of specific noncovalent complex in the brome mosaic virus(BMV) coat proteins would open up a new possibility to investigate the assembly and disassembly of viral capsids.