title: Preliminary neutron and ultrahigh-resolution X-ray diffraction studies of the aspartic proteinase endothiapepsin cocrystallized with a gem-diol inhibitor.
abstract: Endothiapepsin has been cocrystallized with the gem-diol inhibitor PD-135,040 in a low solvent-content (39%) unit cell, which is unprecedented for this enzyme-inhibitor complex and enables ultrahigh-resolution (1.0 A) X-ray diffraction data to be collected. This atomic resolution X-ray data set will be used to deduce the protonation states of the catalytic aspartate residues. A room-temperature neutron data set has also been collected for joint refinement with a room-temperature X-ray data set in order to locate the H/D atoms at the active site.
authors: Spallation Neutron Source, Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, TN 37831, USA.
authors: Han-Fang
authors: HF
authors: Tuan
authors: Peter
authors: P
authors: Erskine
authors: Paul
authors: P
authors: Langan
authors: Jon
authors: J
authors: Cooper
authors: Leighton
authors: L
authors: Coates
mesh_terms: D016282:Aspartic Acid Endopeptidases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D001665:Binding Sites; D003460:Crystallization; D004791:Enzyme Inhibitors / Q000737:chemistry*; D007093:Imidazoles / Q000737:chemistry*; D015394:Molecular Structure; D009025:Morpholines / Q000737:chemistry*; D033363:Neutron Diffraction; D011485:Protein Binding; D014961:X-Ray Diffraction
chemical_list: D004791:Enzyme Inhibitors; D007093:Imidazoles; D009025:Morpholines; C480723:PD-135,040; D016282:Aspartic Acid Endopeptidases; C042466:Endothia aspartic proteinase