Direct Observation of Phenylalanine Orientations in Statherin Bound to Hydroxyapatite Surfaces

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• 作者：Tobias Weidner ; Manish Dubey ; Nicholas F. Breen ; Jason Ash ; J. E. Baio ; Cherno Jaye ; Daniel A. Fischer ; Gary P. Drobny ; David G. Castner
• 刊名：The Journal of the American Chemical Society
• 出版年：2012
• 出版时间：May 30, 2012
• 年：2012
• 卷：134
• 期：21
• 页码：8750-8753
• 全文大小：264K
• 年卷期：v.134,no.21(May 30, 2012)
• ISSN：1520-5126

文摘

Extracellular biomineralization proteins such as salivary statherin control the growth of hydroxyapatite (HAP), the principal component of teeth and bones. Despite the important role that statherin plays in the regulation of hard tissue formation in humans, the surface recognition mechanisms involved are poorly understood. The protein鈥搒urface interaction likely involves very specific contacts between the surface atoms and the key protein side chains. This study demonstrates for the first time the power of combining near-edge X-ray absorption fine structure (NEXAFS) spectroscopy with element labeling to quantify the orientation of individual side chains. In this work, the 15 amino acid N-terminal binding domain of statherin has been adsorbed onto HAP surfaces, and the orientations of phenylalanine rings F7 and F14 have been determined using NEXAFS analysis and fluorine labels at individual phenylalanine sites. The NEXAFS-derived phenylalanine tilt angles have been verified with sum frequency generation spectroscopy.