New biochemical insight of conserved water molecules at catalytic and structural Zn2+ ions in human matrix metalloproteinase-I: a study by MD-simulation.

Human matrix metalloproteinase (MMP)-1 or collagenase-1 plays a significant role in embryonic development, tissue remodeling, and is also involved in several diseases like arthritis, metastasis, etc. Molecular dynamics simulation studies on hMMP-1 X-ray structures (PDB Id. 1CGE, 1CGF, 1CGL, 1HFC, and 2TCL) suggest that the three conserved water molecules (WH/1, WI, WS) are coordinated with catalytic zinc (ZnC), and one water molecule (W) is associated at structural zinc ion (ZnS). Transition of the coordination geometry around ZnC from tetrahedral to octahedral and tetrahedral to trigonal bipyramidal at ZnS are also observed during the dynamics. Recognition of two zinc ions through water mediated bridges (ZnC - WH (W1)…W2….H183 - ZnS) and stabilization of secondary coordination zone around the metal ions indicates the possibility of ZnC…ZnS coupled catalytic mechanism in hMMP-I. This study not only reveals a functionally important role of conserved water molecules in hMMP-I but also highlights the involvement of other non catalytic residues, such as S172 and D170 in the catalytic mechanism. The results obtained in this study could be relevant for importance of conserved water mediated recognition site of the sequence residue id. 202(RWTNNFREY)210, interaction of W(tryptophan)203 to zinc bound histidine, their influence on the water molecules that are involved in bridging between ZnC and ZnS, and structure-based design of specific hMMP inhibitors. Graphical abstract Water mediated recognition of structural and catalytic zinc ions of hMMP-1 structure (MD simulatated conformation).