title: Antimicrobial activity and stability of protonectin with D-amino acid substitutions.
abstract: The misuse and overuse of antibiotics result in the emergence of resistant bacteria and fungi, which make an urgent need of the new antimicrobial agents. Nowadays, antimicrobial peptides have attracted great attention of researchers. However, the low physiological stability in biological system limits the application of naturally occurring antimicrobial peptides as novel therapeutics. In the present study, we synthesized derivatives of protonectin by substituting all the amino acid residues or the cationic lysine residue with the corresponding D-amino acids. Both the D-enantiomer of protonectin (D-prt) and D-Lys-protonectin (D-Lys-prt) exhibited strong antimicrobial activity against bacteria and fungi. Moreover, D-prt showed strong stability against trypsin, chymotrypsin and the human serum, while D-Lys-prt only showed strong stability against trypsin. Circular dichroism analysis revealed that D-Lys-prt still kept typical α-helical structure in the membrane mimicking environment, while D-prt showed left hand α-helical structure. In addition, propidium iodide uptake assay and bacteria and fungi killing experiments indicated that all D-amino acid substitution or partially D-amino acid substitution analogs could disrupt the integrity of membrane and lead the cell death. In summary, these findings suggested that D-prt and D-Lys-prt might be promising candidate antibiotic agents for therapeutic application against resistant bacteria and fungi infection. Copyright © 2017 European Peptide Society and John Wiley & Sons, Ltd.
authors.affiliation: Key Laboratory of Preclinical Study for New Drugs of Gansu Province, School of Basic Medical Sciences, Institute of Biochemistry and Molecular Biology, School of Life Sciences, Lanzhou University, 222 Tian Shui South Road, Lanzhou, 730000, China.
authors.forename: Shuai
authors.initials: S
authors.lastname: Qiu
authors.affiliation: Key Laboratory of Preclinical Study for New Drugs of Gansu Province, School of Basic Medical Sciences, Institute of Biochemistry and Molecular Biology, School of Life Sciences, Lanzhou University, 222 Tian Shui South Road, Lanzhou, 730000, China.
authors.forename: Ranran
authors.initials: R
authors.lastname: Zhu
authors.affiliation: Key Laboratory of Preclinical Study for New Drugs of Gansu Province, School of Basic Medical Sciences, Institute of Biochemistry and Molecular Biology, School of Life Sciences, Lanzhou University, 222 Tian Shui South Road, Lanzhou, 730000, China.
authors.forename: Yanyan
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: Key Laboratory of Preclinical Study for New Drugs of Gansu Province, School of Basic Medical Sciences, Institute of Biochemistry and Molecular Biology, School of Life Sciences, Lanzhou University, 222 Tian Shui South Road, Lanzhou, 730000, China.
authors.forename: Xiaoping
authors.initials: X
authors.lastname: An
authors.affiliation: Key Laboratory of Preclinical Study for New Drugs of Gansu Province, School of Basic Medical Sciences, Institute of Biochemistry and Molecular Biology, School of Life Sciences, Lanzhou University, 222 Tian Shui South Road, Lanzhou, 730000, China.
authors.forename: Fengjing
authors.initials: F
authors.lastname: Jia
authors.affiliation: Key Laboratory of Preclinical Study for New Drugs of Gansu Province, School of Basic Medical Sciences, Institute of Biochemistry and Molecular Biology, School of Life Sciences, Lanzhou University, 222 Tian Shui South Road, Lanzhou, 730000, China.
authors.forename: Jinxiu
authors.initials: J
authors.lastname: Peng
authors.affiliation: Key Laboratory of Preclinical Study for New Drugs of Gansu Province, School of Basic Medical Sciences, Institute of Biochemistry and Molecular Biology, School of Life Sciences, Lanzhou University, 222 Tian Shui South Road, Lanzhou, 730000, China.
authors.forename: Zelin
authors.initials: Z
authors.lastname: Ma
authors.affiliation: Key Laboratory of Preclinical Study for New Drugs of Gansu Province, School of Basic Medical Sciences, Institute of Biochemistry and Molecular Biology, School of Life Sciences, Lanzhou University, 222 Tian Shui South Road, Lanzhou, 730000, China.
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Zhu
authors.affiliation: Key Laboratory of Preclinical Study for New Drugs of Gansu Province, School of Basic Medical Sciences, Institute of Biochemistry and Molecular Biology, School of Life Sciences, Lanzhou University, 222 Tian Shui South Road, Lanzhou, 730000, China.
authors.forename: Jiayi
authors.identifier: http://orcid.org/0000-0003-0749-9214
authors.initials: J
authors.lastname: Wang
authors.affiliation: Key Laboratory of Preclinical Study for New Drugs of Gansu Province, School of Basic Medical Sciences, Institute of Biochemistry and Molecular Biology, School of Life Sciences, Lanzhou University, 222 Tian Shui South Road, Lanzhou, 730000, China.
authors.forename: Jinhuan
authors.initials: J
authors.lastname: Su
authors.affiliation: Key Laboratory of Preclinical Study for New Drugs of Gansu Province, School of Basic Medical Sciences, Institute of Biochemistry and Molecular Biology, School of Life Sciences, Lanzhou University, 222 Tian Shui South Road, Lanzhou, 730000, China.
authors.forename: Qingjun
authors.initials: Q
authors.lastname: Wang
authors.affiliation: The People's Hospital in Gansu Province, 204 West Donggang Road, Lanzhou, 730000, China.
authors.forename: Hailin
authors.initials: H
authors.lastname: Wang
authors.affiliation: The People's Hospital in Gansu Province, 204 West Donggang Road, Lanzhou, 730000, China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Li
authors.affiliation: Key Laboratory of Preclinical Study for New Drugs of Gansu Province, School of Basic Medical Sciences, Institute of Biochemistry and Molecular Biology, School of Life Sciences, Lanzhou University, 222 Tian Shui South Road, Lanzhou, 730000, China.
authors.forename: Kairong
authors.initials: K
authors.lastname: Wang
authors.affiliation: Key Laboratory of Preclinical Study for New Drugs of Gansu Province, School of Basic Medical Sciences, Institute of Biochemistry and Molecular Biology, School of Life Sciences, Lanzhou University, 222 Tian Shui South Road, Lanzhou, 730000, China.
authors.forename: Wenjin
authors.initials: W
authors.lastname: Yan
authors.affiliation: Key Laboratory of Preclinical Study for New Drugs of Gansu Province, School of Basic Medical Sciences, Institute of Biochemistry and Molecular Biology, School of Life Sciences, Lanzhou University, 222 Tian Shui South Road, Lanzhou, 730000, China.
authors.forename: Rui
authors.initials: R
authors.lastname: Wang
mesh_terms: D019943:Amino Acid Substitution; D000890:Anti-Infective Agents / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D023181:Antimicrobial Cationic Peptides / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D001419:Bacteria / Q000187:drug effects*; D002463:Cell Membrane Permeability / Q000187:drug effects; D002942:Circular Dichroism; D015195:Drug Design; D005658:Fungi / Q000187:drug effects*; D008826:Microbial Sensitivity Tests; D008958:Models, Molecular; D017433:Protein Structure, Secondary; D013329:Structure-Activity Relationship; D014862:Wasp Venoms / Q000737:chemistry* / Q000235:genetics
chemical_list: D000890:Anti-Infective Agents; D023181:Antimicrobial Cationic Peptides; D014862:Wasp Venoms
keywords: D-amino acid substitution; antimicrobial peptides; protonectin; stability