Gross D S, Schnier P D, Rodriguez-Cruz S E, Fagerquist C K, Williams E R
Department of Chemistry, University of California, Berkeley 94720, USA.
Proc Natl Acad Sci U S A. 1996 Apr 2;93(7):3143-8. doi: 10.1073/pnas.93.7.3143.
Proton transfer reactivity of isolated charge states of the protein hen egg-white lysozyme shows that multiple distinct conformations of this protein are stable in the gas phase. The reactivities of the 9+ and 10+ charge state ions, formed by electrospray ionization of "native" (disulfide-intact) and "denatured" (disulfide-reduced) solutions, are consistent with values calculated for ions in their crystal structure and fully denatured conformations, respectively. Charge states below 8+ of both forms, formed by proton stripping, have similar or indistinguishable reactivities, indicating that the disulfide-reduced ions fold in the gas phase to a more compact conformation.
鸡蛋清溶菌酶蛋白质分离电荷态的质子转移反应性表明，该蛋白质的多种不同构象在气相中是稳定的。通过对“天然”（二硫键完整）和“变性”（二硫键还原）溶液进行电喷雾电离形成的9+和10+电荷态离子的反应性，分别与根据离子晶体结构和完全变性构象计算的值一致。通过质子剥离形成的两种形式低于8+的电荷态具有相似或难以区分的反应性，这表明二硫键还原离子在气相中折叠成更紧凑的构象。
