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Predicted three‐dimensional structure of the protease inhibitor domain of the Alzheimer's disease β‐amyloid precursor
Author(s) -
Struthers R. Scott,
Kitson David H.,
Hagler Arnold T.
Publication year - 1991
Publication title -
proteins: structure, function, and bioinformatics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.699
H-Index - 191
eISSN - 1097-0134
pISSN - 0887-3585
DOI - 10.1002/prot.340090102
Subject(s) - protease inhibitor (pharmacology) , amyloid precursor protein , chemistry , trypsin inhibitor , homology modeling , protease , context (archaeology) , amyloid (mycology) , protein structure , trypsin , biochemistry , binding site , biophysics , biology , enzyme , alzheimer's disease , genetics , disease , medicine , inorganic chemistry , paleontology , virus , pathology , viral load , antiretroviral therapy
Alzheimer's disease is characterized by the deposition of amyloid β‐protein as plaques and tangles in the brains of its victims. The amyloid precursor can be expressed with or without the inclusion of a protease inhibitor domain, the potential role of which in amyloidogenesis has prompted the generation of a model of its three‐dimensional structure based on the known structure of a related inhibitor. The model structure predicts that the mutated residues are almost entirely on the surface of the inhibitor domain, while conserved residues constitute the hydrophobic core. In addition, several pairs of structurally complementary, or concerted, mutations are seen. These structural features provide strong evidence for the validity of the modeled structure, and it is suggested that the presence of complementary mutations may be used as a criterion for evaluating protein structures built by homology, in addition to the (spatial) location of the mutations. The terminal residues delimiting the domain are among those furthest from the protease binding site and are in close proximity to one another, thus suggesting the ability of the domain to function as a structural cassette within the context of a larger protein. The electrostatic potentials of the inhibitor and of the related bovine pancreatic trypsin inhibitor reveal how two inhibitors with very different net charges can bind with approximately the same binding constant to trypsin and suggest a mutation of trypsin that might selectively enhance the binding of the amyloid inhibitor domain. The model provides a structural basis for understanding the functional roles of residues in the domain and for designing simpler molecules to test as pharmacologic agents for intervention in Alzheimer's disease.