NMR structural studies of bovine and human lactoferrampin, novel antimicrobial peptides from lactoferrin

摘要

Lactoferrin has been identified as a protein with numerous functions, one of which is the ability to inhibit bacterial growth. A pepsin digestion fragment, known as lactoferricin, has already been implicated in the antimicrobial activity of lactoferrin. It is found in the highly cationic N-terminal segment of lactoferrin that distinguishes this protein from other transferrins. Recently, a novel antimicrobial peptide, lactoferrampin, was identified in the sequence of bovine lactoferrin. This fragment is a cationic stretch of 17 amino acids that lies adjacent to lactoferricin on the surface of the N-terminal lobe of the lactoferrin protein. The bovine lactoferrampin peptide (WKLLSKAQEKFGKNKSR) corresponds to residues 268-284 of bovine lactoferrin. The related human peptide (WNLLRQAQEKFGKDKSP) corresponds to residues 269-285 of human lactoferrin and is 70% homologous to the bovine form, but is less cationic.