4apr is a 2 chain structure with sequence from Atcc 52807. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.
Publication Abstract from PubMed
The three-dimensional structures of the complexes of the aspartic proteinase from Rhizopus chinensis (Rhizopuspepsin, EC 3.4.23.6) with pepstatin and two pepstatin-like peptide inhibitors of renin have been determined by X-ray diffraction methods and refined by restrained least-squares procedures. The inhibitors adopt an extended conformation and lie in the deep groove located between the two domains of the enzyme. Inhibitor binding is accompanied by a conformational change at the "flap," a beta-hairpin loop region, that projects over the binding cleft and closes down over the inhibitor, excluding water molecules from the vicinity of the scissile bond. The hydroxyl group of the central statyl residue of the inhibitors replaces the water molecule found between the two active aspartates, Asp-35 and Asp-218, in the native structure. The refined structures provide additional data to define the specific subsites of the enzyme and also show a system of hydrogen bonding to the inhibitor backbone similar to that observed for a reduced inhibitor.
Structures of complexes of rhizopuspepsin with pepstatin and other statine-containing inhibitors.,Suguna K, Padlan EA, Bott R, Boger J, Parris KD, Davies DR Proteins. 1992 Jul;13(3):195-205. PMID:1603809[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
↑Suguna K, Padlan EA, Bott R, Boger J, Parris KD, Davies DR. Structures of complexes of rhizopuspepsin with pepstatin and other statine-containing inhibitors. Proteins. 1992 Jul;13(3):195-205. PMID:1603809 doi:https://dx.doi.org/10.1002/prot.340130303
