title: Effects of L- or D-Pro incorporation into hydrophobic or hydrophilic helix face of amphipathic alpha-helical model peptide on structure and cell selectivity.
abstract: A synthetic amphipathic alpha-helical model peptide, KLW, displays non-cell selective cytotoxicity. To investigate the effects of L- or D-Pro kink incorporation into hydrophobic or hydrophilic helix face of KLW on structure, cell selectivity, and membrane-binding affinity, we designed a series of four peptides, in which Leu(9) and Lys(11) in the hydrophobic and hydrophilic helix face of KLW, respectively, are substituted with L- or D-Pro. A L- or D-Pro substitution (KLW-L9P or KLW-L9p) of Leu(9) at the hydrophobic helix face of KLW induced a more significant reduction in hemolytic activity with improved antibacterial activity than that (KLW-K11P or KLW-K11p) of Lys(11) in the hydrophilic helix face. In addition, D-Pro-containing peptides (KLW-L9p and KLW-K11p) displayed less hemolytic activity than L-Pro-containing peptides (KLW-L9P and KLW-K11P). Tryptophan fluorescence studies revealed that bacterial cell selectivity of KLW-L9P, KLW-L9p, and KLW-K11p is closely related to selective interactions with negatively charged phospholipids. CD analysis revealed that L- or D-Pro incorporation into KLW reduces the alpha-helicity of the peptide and D-Pro incorporation induces more significant disruption in alpha-helical structure than L-Pro incorporation. Our results collectively suggest that D-Pro incorporation into the hydrophobic helix face of non-cell selective amphipathic alpha-helical peptides may be useful for the design of novel antimicrobial peptides possessing high bacterial cell selectivity without hemolytic activity.
authors.affiliation: Department of Bio-Materials, Graduate School and Research Center for Proteineous Materials, Chosun University, 501-759 Kwangju, Republic of Korea.
authors.forename: Yun Mi
authors.initials: YM
authors.lastname: Song
authors.forename: Sung Tae
authors.initials: ST
authors.lastname: Yang
authors.forename: Shin Saeng
authors.initials: SS
authors.lastname: Lim
authors.forename: Yangmee
authors.initials: Y
authors.lastname: Kim
authors.forename: Kyung Soo
authors.initials: KS
authors.lastname: Hahm
authors.forename: Jae Il
authors.initials: JI
authors.lastname: Kim
authors.forename: Song Yub
authors.initials: SY
authors.lastname: Shin
mesh_terms: D020106:Acrylamide / Q000494:pharmacology; D001671:Biochemistry / Q000379:methods; D002942:Circular Dichroism; D004305:Dose-Response Relationship, Drug; D004926:Escherichia coli / Q000378:metabolism; D007700:Kinetics; D008055:Lipids / Q000737:chemistry; D010452:Peptide Biosynthesis; D010455:Peptides / Q000737:chemistry*; D011392:Proline / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D014364:Tryptophan / Q000737:chemistry
chemical_list: D008055:Lipids; D010455:Peptides; D020106:Acrylamide; D014364:Tryptophan; D011392:Proline