Human formyl peptide receptor function. Role of conserved and nonconserved charged residues

In this study, we investigated the role of charged residues in ligand binding interactions of f-Met-Leu-Phe receptors (FPR). Charged residues of FPR, both conserved and nonconserved, which are located close to the membrane interface were mutated to alanine to determine their role in ligand binding. The mutated residues belonged to specific domains of FPR which have previously been implicated in FPR ligand binding interactions. We demonstrate that nonconserved charged residues such as Arg84, Lys85, Arg205 and Asp284 and conserved charge residue Arg163 seem to play a role in ligand binding. However, alteration of nonconserved charged residue Asp106 did not have any effect. In conclusion, specific charged residues of FPR, both conserved nonconserved, may contribute to FPR function either directly or indirectly.