Capriotti Lisa A, Beebe Thomas P, Schneider Joel P
Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, USA.
J Am Chem Soc. 2007 Apr 25;129(16):5281-7. doi: 10.1021/ja070356b. Epub 2007 Mar 31.
Herein, we describe the design and surface-binding characterization of a de novo designed peptide, JAK1, which undergoes surface-induced folding at the hydroxyapatite (HA)-solution interface. JAK1 is designed to be unstructured in buffered saline solution, yet undergo HA-induced folding that is largely governed by the periodic positioning of gamma-carboxyglutamic acid (Gla) residues within the primary sequence of the peptide. Circular dichroism (CD) spectroscopy and analytical ultracentrifugation indicate that the peptide remains unfolded and monomeric in solution under normal physiological conditions; however, CD spectroscopy indicates that in the presence of hydroxyapatite, the peptide avidly binds to the mineral surface adopting a helical structure. Adsorption isotherms indicate nearly quantitative surface coverage and Kd = 310 nM for the peptide-surface binding event. X-ray photoelectron spectroscopy (XPS) coupled with the adsorption isotherm data suggests that JAK1 binds to HA, forming a self-limiting monolayer. This study demonstrates the feasibility of using HA surfaces to trigger the intramolecular folding of designed peptides and represents the initial stages of defining the design rules that allow HA-induced peptide folding.
在此，我们描述了一种全新设计的肽JAK1的设计及其表面结合特性，该肽在羟基磷灰石（HA）-溶液界面发生表面诱导折叠。JAK1在缓冲盐溶液中设计为无结构状态，但会发生HA诱导的折叠，这在很大程度上受肽一级序列中γ-羧基谷氨酸（Gla）残基的周期性定位支配。圆二色性（CD）光谱和分析超速离心表明，该肽在正常生理条件下在溶液中保持未折叠且为单体状态；然而，CD光谱表明，在存在羟基磷灰石的情况下，该肽会 avidly 结合到矿物表面并采用螺旋结构。吸附等温线表明肽-表面结合事件的表面覆盖率接近定量，Kd = 310 nM。X射线光电子能谱（XPS）结合吸附等温线数据表明JAK1与HA结合，形成自限性单层。本研究证明了利用HA表面触发设计肽的分子内折叠的可行性，并代表了定义允许HA诱导肽折叠的设计规则的初始阶段。
