Amino Acid Residues in the αIIb Subunit That Are Critical for Ligand Binding to Integrin αIIbβ3 Are Clustered in the β-Propeller Model

摘要: Abstract Several distinct regions of the integrin αIIb subunit have been implicated in ligand binding. To localize binding sites αIIb, we swapped all 27 predicted loops with corresponding sequences α4 or α5. 19 swapping mutations had no effect on to both fibrinogen and ligand-mimetic antibodies (e.g. LJ-CP3), suggesting that these do not contain major sites. In contrast, remaining 8 completely blocked Ala scanning mutagenesis critical identified more than 30 discontinuous residues repeats 2–4 at boundary between 4 5 as for Interestingly, are clustered β-propeller model, consistent this model. Most located edge upper face propeller, several side propeller domain. None 1, 6, 7, none four putative Ca2+-binding lower surface were important The results map an interface top toroid, centering repeat 3.