Unexpected Active-Site Flexibility in the Structure of Human Neutrophil Elastase in Complex with a New Dihydropyrimidone Inhibitor

作者：Hansen Guido; Gielen Haertwig Heike; Reinemer Peter; Schomburg Dietmar; Harrenga Axel^*; Niefind Karsten

来源：Journal of Molecular Biology, 2011, 409(5): 681-691.

DOI：10.1016/j.jmb.2011.04.047

• human neutrophil elastase
• chronic obstructive
• pulmonary disease
• binding mode
• protein structure

Human neutrophil elastase (HNE), a trypsin-type serine protease, is of pivotal importance in the onset and progression of chronic obstructive pulmonary disease (COPD). COPD encompasses a group of slowly progressive respiratory disorders and is a major medical problem and the fifth leading cause of death worldwide. HNE is a major target for the development of compounds that inhibit the progression of long-term lung function decline in COPD patients.
Here, we present the three-dimensional structure of a potent dihydropyrimidone inhibitor (DHPI) non-covalently bound to FINE at a resolution of 2.0 angstrom. The inhibitor binds to the active site in a unique orientation addressing Si and S2 subsites of the protease. To facilitate further analysis of this binding mode, we determined the structure of the uncomplexed enzyme at a resolution of 1.86 angstrom. Detailed comparisons of the HNE:DHPI complex with the uncomplexed FINE structure and published structures of other elastase:inhibitor complexes revealed that binding of DHPI leads to large conformational changes in residues located in the S2 subsite. The rearrangement of residues Asp95-Leu998 creates a deep, well-defined cavity, which is filled by the P2 moiety of the inhibitor molecule to almost perfect shape complementarity. The shape of the S2 subsite in complex with DHPI clearly differs from all other observed FINE structures. The observed structural flexibility of the S2 subsite is a key feature for the understanding of the binding mode of DHPIs in general and the development of new FINE selective inhibitors.

• 出版日期2011-6-24