Lactoferrampin, an antimicrobial peptide of bovine lactoferrin, exerts its candidacidal activity by a cluster of positively charged residues at the C-terminus in combination with a helix-facilitating N-terminal part

Biol Chem. 2005 Feb;386(2):137-42. doi: 10.1515/BC.2005.017.

Abstract

The antimicrobial activity of bovine lactoferrin (bLF) is attributed to lactoferricin, which is situated in the N1-domain of bLF. Recently, another antimicrobial domain consisting of residues 268-284, designated lactoferrampin (LFampin), has been identified in the N1-domain of bLF, which exhibited antimicrobial activity against Candida albicans and several bacteria. In the present study, the candidacidal activity of a series of peptides spanning this antimicrobial domain was investigated in relation to the charge and the capacity to form a helical conformation in hydrophobic environments. C-Terminal truncation of LFampin resulted in a drastic decrease in candidacidal activity. Positively charged residues clustered at the C-terminal side of the LFampin domain appeared to be crucial for the candidacidal activity. The ability to adopt helical conformations did not change when LFampin was truncated at the C-terminal side. N-Terminally truncated LFampin peptides, truncated up to the sequence 270-284, were more reluctant to adopt a helical conformation. Therefore, we conclude that the C-terminal part of LFampin 265-284, which is the most active peptide, is crucial for its candidacidal activity, due to the presence of clustered positive charges, and that the N-terminal part is essential for activity as it facilitates helix formation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Antifungal Agents / chemistry*
  • Antifungal Agents / pharmacology
  • Candida albicans / drug effects*
  • Circular Dichroism
  • Flow Cytometry
  • Hemolysis / drug effects
  • Humans
  • Lactoferrin
  • Lactoglobulins / chemical synthesis
  • Lactoglobulins / chemistry*
  • Lactoglobulins / pharmacology
  • Peptide Fragments / chemical synthesis
  • Peptide Fragments / chemistry*
  • Peptide Fragments / pharmacology
  • Protein Structure, Secondary

Substances

  • Antifungal Agents
  • Lactoglobulins
  • Peptide Fragments
  • lactoferrampin
  • Lactoferrin