. . . . . . . . . . . . . . . . "The single amino acid residue number 96 in the SH3 domain of Fyn regulates its affinity and specificity in binding to HIV-1 Nef" . "HIV-1 Nef binds to the SH3 domain of Fyn through its proline-rich (PXXP) motifs between amino acid residues 65 and 82; this binding enhances viral replication but not down-regulation of CD4" . "Crystal structure studies reveal the conserved PXXP sequence motif of HIV-1 Nef is part of a polyproline type II helix that is required for Nef binding to the SH3 domain of Fyn" . "Co-crystal Structure; Reconstituted Complex" . "BioGRID" . "binds" .