Premium
Effect of Leucine and Lysine substitution on the antimicrobial activity and evaluation of the mechanism of the HPA3NT3 analog peptide
Author(s) -
Gopal Ramamourthy,
Park SeongCheol,
Ha KyeoungJu,
Cho Seung Joo,
Kim Si Wouk,
Song Peter I.,
Nah JaeWoon,
Park Yoonkyung,
Hahm KyungSoo
Publication year - 2009
Publication title -
journal of peptide science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 66
eISSN - 1099-1387
pISSN - 1075-2617
DOI - 10.1002/psc.1155
Subject(s) - peptide , chemistry , circular dichroism , stereochemistry , amino acid , vesicle , biochemistry , membrane
In this study, a HPA3NT3‐analog (FKKLKKLFKKILKLK‐NH 2 ) peptide was designed. In this analog, two Trp residues (positions 12, 14) were replaced with Leu, and Arg and Asn (positions 3, 13) were replaced with Lys to investigate the role of amino acid substitution and increased cationicity on antimicrobial and hemolytic activities. In fungal and Gram‐negative bacterial cells, HPA3NT3‐analog activity was unchanged or slightly enhanced when compared to the HPA3NT3 peptide. In addition, a twofold decrease in activity against Gram‐positive bacteria was observed. The HPA3NT3‐analog also induced less hemolysis (4.2%) than the HPA3NT3 peptide (71%) at 200 µ M . Circular dichroism (CD) spectra revealed that the HPA3NT3‐analog peptide had an unordered structure in buffer and egg yolk L‐2‐phosphatidyl choline (EYPC), but adapted an α‐helical conformation in 50% 2,2,2‐trifluoroethanol (TFE) and negatively charged egg yolk L‐2‐phosphatidyl glycerol (EYPG), while the parent peptide showed an ordered structure in the EYPC. Additionally, the HPA3NT3‐analog peptide induced the leakage of calcein from egg yolk L‐2‐phosphatidyl ethanolamine (EYPE)/EYPG (7:3 w/w) large unilamellar vesicles (LUVs); however, the activity was slightly weaker than that of the HPA3NT3 peptide. The molecular dynamics (MD) structures revealed that the amino acid substitutions induced a significant variation in peptide structure. These results suggest that the substitutions of Arg and Asn with Lys and two Trp with Leu resulted in small changes in HPA3NT3‐analog activity and significant decreases in hemolytic activity. Copyright © 2009 European Peptide Society and John Wiley & Sons, Ltd.