Department of Biochemistry and Molecular Biology, Penn State University College of Medicine, Hershey, Pennsylvania 17022, USA.
Protein Sci. 2011 Feb;20(2):327-35. doi: 10.1002/pro.563.
The folding initiation mechanism of human bile acid-binding protein (BABP) has been examined by (19) F NMR. Equilibrium unfolding studies of BABP labeled with fluorine at all eight of its phenylalanine residues showed that at least two sites experience changes in solvent exposure at high denaturant concentrations. Peak assignments were made by site-specific 4FPhe incorporation. The resonances for proteins specifically labeled at Phe17, Phe47, and Phe63 showed changes in chemical shift at denaturant concentrations at which the remaining five phenylalanine residues appear to be fully solvent-exposed. Phe17 is a helical residue that was not expected to participate in a folding initiation site. Phe47 and Phe63 form part of a hydrophobic core region that may be conserved as a site for folding initiation in the intracellular lipid-binding protein family.
(19)F NMR 研究了人胆汁酸结合蛋白(BABP)的折叠起始机制。用氟标记 BABP 的所有 8 个苯丙氨酸残基的平衡解折叠研究表明,在高变性剂浓度下,至少有两个位点的溶剂暴露发生变化。通过特异性 4FPhe 掺入进行峰分配。在变性剂浓度下,专门标记在 Phe17、Phe47 和 Phe63 上的蛋白质的共振发生了化学位移变化,而其余五个苯丙氨酸残基似乎完全暴露在溶剂中。Phe17 是一个螺旋残基,预计不会参与折叠起始位点。Phe47 和 Phe63 形成疏水核心区域的一部分,可能作为细胞内脂质结合蛋白家族折叠起始的位点保守。