Li Yingjie, Kim Seho, Brodsky Barbara, Baum Jean
Department of Chemistry, Rutgers University, Piscataway, New Jersey 08854, USA.
J Am Chem Soc. 2005 Aug 3;127(30):10490-1. doi: 10.1021/ja052801d.
It is technically challenging to detect low-population partially disordered species that are in equilibrium with the folded and unfolded states. Residue-specific translational diffusion experiments measured by pulsed field gradient NMR have been used to detect the presence, and define the conformation, of such equilibrium intermediates. The experiment is demonstrated for equilibrium solutions of related triple helical peptides that model a small region of type I collagen with and without a mutation known to cause osteogenesis imperfecta. The data show that residue-specific diffusion coefficients of an interconverting trimer to monomer system can allow discrimination between a simple two-state model and more complex multistate models involving partially disordered intermediates.
检测与折叠态和未折叠态处于平衡的低丰度部分无序物种在技术上具有挑战性。通过脉冲场梯度核磁共振测量的残基特异性平移扩散实验已被用于检测此类平衡中间体的存在并确定其构象。该实验在相关三螺旋肽的平衡溶液中得到了验证，这些肽模拟了I型胶原蛋白的一个小区域，有或没有已知会导致成骨不全的突变。数据表明，相互转化的三聚体到单体系统的残基特异性扩散系数可以区分简单的两态模型和涉及部分无序中间体的更复杂的多态模型。
