Effect of amino acids near the RGD sequence on binding activities between αIIbβ3 integrin and fibrinogen in the presence of RGD-containing synthetic peptides from elegantin and angustatin.

•PRGDMP-type peptides more strongly inhibited the platelet aggregation than ARGDDX-type peptides.•Cyclic peptide (CPRGDMPC) most strongly inhibited the platelet aggregation and binding between αIIbβ3 and fibrinogen.•Cyclic peptide (CPRGDMPC) demonstrated a stronger inhibitory and more stable effect in the presence of Mg2+ compared with Ca2+.