Atrolysin C is a P-I
snake venom metalloproteinase (SVMP) from Crotalus atrox
venom, which efficiently degrades capillary basement membranes, extracellular matrix, and
cell surface proteins to produce
hemorrhage. The tissue inhibitors of
metalloproteinases (TIMPs) are effective inhibitors of
matrix metalloproteinases which share some structural similarity with the SVMPs. In this work, we evaluated the inhibitory profile of
TIMP-1,
TIMP-2, and the N-terminal domain of
TIMP-3 (N-TIMP-3) on the proteolytic activity of
atrolysin C and analyzed the structural requirements and molecular basis of
inhibitor-enzyme interaction using molecular modeling. While
TIMP-1 and
TIMP-2 had no inhibitory activity upon
atrolysin C, the N-terminal domain of
TIMP-3 (N-TIMP-3) was a potent inhibitor with a K(i) value of approximately 150nM. The predicted docking structures of
atrolysin C and TIMPs were submitted to molecular dynamics simulations and the complex
atrolysin C/N-TIMP-3 was the only one that maintained the inhibitory conformation. This study is the first to shed light on the structural determinants required for the interaction between a SVMP and a TIMP, and suggests a structural basis for
TIMP-3 inhibitory action and related
proteins such as the ADAMs.