Collagen-ligand interaction in dentinal adhesion: computer visualization and analysis

The objective of this study was to characterize the interactions of selecte d ligand molecules with collagen structure through computer visualization o f the reacting molecules and the resulting complexes. Five ligand molecules were studied. They were 2-Hydroxyethyl methacrylate, Glutaraldehyde-HEMA a dduct, Glyceryl dimethacrylate, Methacryloyloxyethyl maleate and Acryloylox yethyl citraconate. These ligands were selected with oxygen as a common het eroatom for a reactive or functional site. Energy minimized 3-D structures of the molecules were generated by Sybyl molecular modeling software. The s tructures were subjected to a systematic conformational search, yielding co nformations of the molecules with a common recognition site with both steri c and electrostatic complementarity to appropriate receptor sites in a type I collagen molecular structure. The ligands were also docked to collagen r eceptor by autodock procedures and the receptor sites where docking occurre d were evaluated. The energy of the molecules and their complexes with coll agen was evaluated and compared. The computer visualization results reveal that steric complementarity between receptor sites in collagen and optimall y configured ligands may be the basis of micromechanical bonding between co llagen and the ligands. Typically, ligands docked on the cavities of collag en molecular surface and wrapped around the cavities which follow the helic al turns of the collagen macromolecule. In addition, analysis of electrosta tic potential features revealed electrostatic complementarity as an additio nal source of interaction. Hydrogen bonds between ligands and collagen mole cule were detected in the complexes of several of the conformations of all the ligands. Thus computer simulation studies show that steric and electros tatic complementarity and consequent interactions form the potential basis of binding between dentin adhesive ligands and type I collagen. (C) 2001 El sevier Science Ltd. All rights reserved.