Evaluation of the role of proline residues flanking the RGD motif of dendroaspin, an inhibitior of platelet aggregation and cell adhesion.
The effect of a panel of proline mutants of dendroaspin, an inhibitor of platelet aggregation and cell adhesion, including A(42)-dendroaspin, A(47)-dendroaspin, A(49)-dendroaspin, A(42,47)-dendroaspin and A(47,49)-dendroaspin, was investigated using platelet-aggregation and cell-adhesion assays. Here we show that a single alanine-for-proline substitution did not affect potency when measured as the ability either to inhibit platelet aggregation induced by ADP (IC(50) approximately 170 nM) or to block transfected A375-SM cell adhesion to fibrinogen in the presence of Mn(2+) as compared with wild-type dendroaspin. By comparison, double proline substitution with alanines significantly reduced the potency in both assays by approx. 5-8-fold. These observations, therefore, suggest that proline residues flanking the RGD motif in dendroaspin and other RGD-containing venom proteins, e.g. disintegrins, may contribute to maintaining a favourable conformation for the solvent-exposed RGD site for its recognition by integrin receptors.
Lu
X
X
Thrombosis Research Institute, Manresa Road, London, SW3 6LR, UK. xlu@tri-london.ac.uk
Sun
Y
Y
Shang
D
D
Wattam
B
B
Egglezou
S
S
Hughes
T
T
Hyde
E
E
Scully
M
M
Kakkar
V
V
D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D002448:Cell Adhesion / Q000187:drug effects; D004546:Elapid Venoms / Q000737:chemistry / Q000235:genetics / Q000494:pharmacology*; D005069:Evaluation Studies as Topic; D005340:Fibrinogen / Q000378:metabolism; D006801:Humans; D016023:Integrins / Q000378:metabolism; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009842:Oligopeptides; D010974:Platelet Aggregation / Q000187:drug effects*; D010975:Platelet Aggregation Inhibitors / Q000737:chemistry / Q000494:pharmacology*; D011392:Proline / Q000235:genetics / Q000494:pharmacology*; D011994:Recombinant Proteins / Q000737:chemistry / Q000494:pharmacology; D017386:Sequence Homology, Amino Acid; D014407:Tumor Cells, Cultured
D004546:Elapid Venoms; D016023:Integrins; D009842:Oligopeptides; D010975:Platelet Aggregation Inhibitors; D011994:Recombinant Proteins; C074772:mambin; C047981:arginyl-glycyl-aspartic acid; D005340:Fibrinogen; D011392:Proline