Interaction of Heparin with a Synthetic Pentadecapeptide from the C-Terminal Heparin-Binding Domain of Fibronectin

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• 作者：Siva P. Hari ; Heather McAllister ; Wei-Lien Chuang ; Marie Dvorak Christ ; and Dallas L. Rabenstein
• 刊名：Biochemistry
• 出版年：2000
• 出版时间：April 4, 2000
• 年：2000
• 卷：39
• 期：13
• 页码：3763 - 3773
• 全文大小：162K
• 年卷期：v.39,no.13(April 4, 2000)
• ISSN：1520-4995

文摘

The synthetic pentadecapeptide FN-C/H II (KNNQKSEPLIGRKKT-NH₂) has the sequenceof the carboxy-terminal heparin-binding domain of module III₁₄ of fibronectin. Interaction of FN-C/H IIwith bovine lung heparin has been studied by ¹H and ²³Na NMR spectroscopy and by heparin affinitychromatography. FN-C/H II binds to heparin from pD <2 up to pD ~10; at higher pD, the bindingdecreases as the lysine side-chain ammonium groups are titrated. Na⁺ counterions are displaced from thecounterion condensation volume that surrounds sodium heparinate by FN-C/H II, which provides directevidence that the binding involves electrostatic interactions. The pK_A values for each of the five ammoniumgroups of FN-C/H II increase upon binding to heparin which, together with chemical shift data, indicatesthat the binding involves both delocalized and direct electrostatic interactions between ammonium groupsof FN-C/H II and carboxylate and/or sulfate groups of heparin. NMR data also provide evidence for thedirect interaction of the guanidinium group of the arginine side chain with anionic sites on heparin. Theaffinity of heparin for FN-C/H II and for 13 analogue peptides in which lysine and arginine residues weresystematically substituted with alanine increases as the number of basic residues increases. The relativecontribution of each lysine and arginine to the affinity of heparin for FN-C/H II is R¹² > K¹³ > K¹⁴ >K¹ > K⁵. Nuclear Overhauser enhancement (NOE) data indicate that, while FN-C/H II is largelyunstructured in aqueous solution, the bound peptide interconverts among overlapping, turn-like conformations over the L⁹ - T¹⁵ segment of the peptide. NOE data for the interaction of FN-C/H II with a heparin-derived hexasaccharide, together with the number of Na⁺ ions displaced from heparin by FN-C/H II asdetermined by ²³Na NMR, indicates that the peptide binds to a hexasaccharide segment of heparin. IdenticalNMR and heparin affinity chromatography results were obtained for the interaction of FN-C/H II and itsD-amino acid analogue peptide with heparin, which is of interest for the potential use of peptides astherapeutic agents for diseases in which cell adhesion plays a critical role.