Sciex, 55 Glen Cameron Road, L3T 1P2, Thornhill, Ontario, Canada.
J Am Soc Mass Spectrom. 1993 Aug;4(8):616-23. doi: 10.1016/1044-0305(93)85025-S.
A method for the determination of cross sections for gas-phase protein ions, based on the energy loss of ions as they pass through a collision gas, is described. A simple model relates the energy loss to the number of collisions and hence the cross section. Results from a Monte Carlo model that support the validity of this approach are described. Experimental cross sections are reported for motilin, ubiquitin, cytochrome c, myoglobm, and bovine serum albumin. Cross sections range from approximately 800 Å(2) for motilin to approximately 14,000 Å(2) for bovine serum albumin and generally increase with the number of charges on the ion. Cytochrome c ions from aqueous solution show somewhat smaller cross sections than ions formed from solutions of higher organic content, suggesting that the gas-phase ions may retain some memory of their solution conformation.
一种基于离子在穿过碰撞气体时能量损失来测定气相蛋白离子截面的方法被描述。一个简单的模型将能量损失与碰撞次数相关联，从而与截面相关联。描述了支持这种方法有效性的蒙特卡罗模型的结果。报道了胃动素、泛素、细胞色素 c、肌红蛋白和牛血清白蛋白的实验截面。截面范围从大约 800 Å(2)的胃动素到大约 14000 Å(2)的牛血清白蛋白，并且通常随着离子上的电荷数增加而增加。来自水溶液的细胞色素 c 离子的截面比来自高有机含量溶液形成的离子的截面小一些，这表明气相离子可能保留其溶液构象的一些记忆。
