Primary Citation of Related Structures:   1LYW
PubMed Abstract: 
The crystal structure of a catalytically inactive form of cathepsin D (CatDhi) has been obtained at pH 7.5. The N-terminal strand relocates by 30 A from its position in the interdomain beta-sheet and inserts into the active site cleft, effectively blocki ...
The crystal structure of a catalytically inactive form of cathepsin D (CatDhi) has been obtained at pH 7.5. The N-terminal strand relocates by 30 A from its position in the interdomain beta-sheet and inserts into the active site cleft, effectively blocking substrate access. CatDhi has a five-stranded interdomain beta-sheet and resembles Intermediate 3, a hypothetical structure proposed to be transiently formed during proteolytic activation of the proenzyme precursor. Interconversion between active and inactive forms of CatD is reversible and may be regulated by an ionizable switch involving the carboxylate side chains of Glu 5, Glu 180, and Asp 187. Our findings provide a structural basis for the pH-dependent regulation of aspartic proteinase activity and suggest a novel mechanism for pH-dependent modulation of substrate specificity.
Related Citations: 
Crystal Structures of Native and Inhibited Forms of Human Cathepsin D: Implications for Lysosomal Targeting and Drug Design Baldwin, E.T., Bhat, T.N., Gulnik, S., Hosur, M.V., Sowder II, R.C., Cachau, R.E., Collins, J., Silva, A.M., Erickson, J.W. (1993) Proc Natl Acad Sci U S A 90: 6796
Human Liver Cathepsin D. Purification, Crystallization and Preliminary X-Ray Diffraction Analysis of a Lysosomal Enzyme Gulnik, S., Baldwin, E.T., Tarasova, N., Erickson, J. (1992) J Mol Biol 227: 265
Organizational Affiliation: 
Structural Biochemistry Program, SAIC Frederick, National Cancer Institute, Maryland 21702-1201, USA.