The fibronectin-binding protein A promotes bacterial attachment to multiple substrates, such as fibronectin, fibrinogen, elastin peptides and tropoelastin, confering to Staphylococcus aureus the ability to invade endothelial cells. The peptide also promotes adherence to and aggregation of activated platelets.H-Phe-Asn-Lys-His-Thr-Glu-Ile-Ile-Glu-Glu-Asp-Thr-Asn-Lys-Asp-Lys-Pro-Ser-Tyr-Gln-Phe-Gly-Gly-His-Asn-Ser-Val-Asp-Phe-Glu-Glu-Asp-Thr-Leu-Pro-Lys-Val-OH or H-FNKHTEIIEEDTNKDKPSYQFGGHNSVDFEEDTLPKV-OH