1xn3
Crystal structure of Beta-secretase bound to a long inhibitor with additional upstream residues.
Structural highlights
FunctionBACE1_HUMAN Responsible for the proteolytic processing of the amyloid precursor protein (APP). Cleaves at the N-terminus of the A-beta peptide sequence, between residues 671 and 672 of APP, leads to the generation and extracellular release of beta-cleaved soluble APP, and a corresponding cell-associated C-terminal fragment which is later released by gamma-secretase.[1] [2] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedMemapsin 2 (beta-secretase) is the membrane-anchored aspartic protease that initiates the cleavage of beta-amyloid precursor protein (APP), leading to the production of amyloid-beta (Abeta), a major factor in the pathogenesis of Alzheimer's disease. The active site of memapsin 2 has been shown, with kinetic data and crystal structures, to bind to eight substrate residues (P(4)-P(4)'). We describe here that the addition of three substrate residues from P(7) to P(5) strongly influences the hydrolytic activity by memapsin 2 and these subsites prefer hydrophobic residues, especially tryptophan. A crystal structure of memapsin 2 complexed with a statine-based inhibitor spanning P(10)-P(4)' revealed the binding positions of P(5)-P(7) residues. Kinetic studies revealed that the addition of these substrate residues contributes to the decrease in K(m) and increase in k(cat) values, suggesting that these residues contribute to both substrate recognition and transition-state binding. The crystal structure of a new inhibitor, OM03-4 (K(i) = 0.03 nM), bound to memapsin 2 revealed the interaction of a tryptophan with the S(6) subsite of the protease. Structural locations and functional roles of new subsites S5, S6, and S7 in memapsin 2 (beta-secretase).,Turner RT 3rd, Hong L, Koelsch G, Ghosh AK, Tang J Biochemistry. 2005 Jan 11;44(1):105-12. PMID:15628850[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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