Structure and protein design of a human platelet function inhibitor.
Hematophagous arthropods secrete a salivary apyrase that inhibits platelet activation by catabolizing ADP released from damaged tissues and blood cells. We report the X-ray crystal structures of a human enzyme of the soluble apyrase family in its apo state and bound to a substrate analog. The structures reveal a nucleotide binding domain comprising a five-blade beta propeller, binding determinants of the substrate and the active site, and an unusual calcium binding site with a potential regulatory function. Using a comparative structural biology approach, we were able to redesign the human apyrase so as to enhance its ADPase activity by more than 100-fold. The engineered enzyme is a potent inhibitor of platelet aggregation and may serve as the basis for the development of a new class of antithrombotic agents.
Department of Biochemistry, Weill Medical College of Cornell University, New York, NY 10021, USA.
Jiayin
J
Dai
Jie
J
Liu
Yiqun
Y
Deng
Thomas M
TM
Smith
Min
M
Lu
D000595:Amino Acid Sequence; D000818:Animals; D001081:Apyrase / Q000737:chemistry* / Q000378:metabolism*; D001665:Binding Sites; D001792:Blood Platelets / Q000502:physiology*; D002118:Calcium / Q000378:metabolism; D018360:Crystallography, X-Ray; D006801:Humans; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010974:Platelet Aggregation / Q000502:physiology; D010975:Platelet Aggregation Inhibitors / Q000737:chemistry* / Q000378:metabolism*; D011487:Protein Conformation; D016415:Sequence Alignment; D013379:Substrate Specificity
D010975:Platelet Aggregation Inhibitors; D001081:Apyrase; D002118:Calcium