Optimization of oncocin for antibacterial activity using a SPOT synthesis approach: extending the pathogen spectrum to Staphylococcus aureus.
The identification of lead molecules against multidrug-resistant bacteria ensuing the development of novel antimicrobial drugs is an urgent task. Proline-rich antimicrobial peptides are highly active in vitro and in vivo, but only against a few Gram-negative human pathogens, with rather weak activities against Pseudomonas aeruginosa and Staphylococcus aureus. This reduced level of efficacy could be related to inadequate uptake mechanisms or structural differences of the intracellular target proteins, i.e., the 70S ribosome or chaperone DnaK. Here we synthesized peptide arrays on cellulose membranes using cleavable linkers to release the free individual peptides for further antimicrobial tests. Thus, a library of singly substituted oncocin analogs was produced by replacing each residue by all other 19 canonical amino acids yielding a set of 361 individual peptides to be evaluated against a luminescent P. aeruginosa strain. Thirteen substitutions appeared promising and their improved antibacterial activities were confirmed for different bacteria after larger scale synthesis of these analogs. By combining two favorable substitutions into one peptide, we finally obtained an oncocin analog that was ten times more active against P. aeruginosa and even 100-fold more active against S. aureus than the original oncocin, providing minimal inhibitory concentrations of 4-8 and 0.5 µg/mL, respectively.
Institute of Bioanalytical Chemistry, Faculty of Chemistry and Mineralogy, Universität Leipzig, Deutscher Platz 5, 04103, Leipzig, Germany. daniel.knappe@bbz.uni-leipzig.de.|Center for Biotechnology and Biomedicine, Universität Leipzig, Deutscher Platz 5, 04103, Leipzig, Germany. daniel.knappe@bbz.uni-leipzig.de.
Daniel
D
Knappe
Karlsruhe Institute of Technology (KIT), Institute of Functional Interfaces and Institute of Microstructure Technology, P.O. Box 3640, 76021, Karlsruhe, Germany.
Serge
S
Ruden
Institute of Bioanalytical Chemistry, Faculty of Chemistry and Mineralogy, Universität Leipzig, Deutscher Platz 5, 04103, Leipzig, Germany.|Center for Biotechnology and Biomedicine, Universität Leipzig, Deutscher Platz 5, 04103, Leipzig, Germany.
Stefanie
S
Langanke
School of Chemistry, Monash University, Clayton, VIC, 3800, Australia.
Tarun
T
Tikkoo
Institute of Bioanalytical Chemistry, Faculty of Chemistry and Mineralogy, Universität Leipzig, Deutscher Platz 5, 04103, Leipzig, Germany.|Center for Biotechnology and Biomedicine, Universität Leipzig, Deutscher Platz 5, 04103, Leipzig, Germany.
Jennifer
J
Ritzer
Karlsruhe Institute of Technology (KIT), Institute for Applied Computer Science, P.O. Box 3640, 76021, Karlsruhe, Germany.
Ralf
R
Mikut
School of Chemistry, Monash University, Clayton, VIC, 3800, Australia.
Lisandra L
LL
Martin
Institute of Bioanalytical Chemistry, Faculty of Chemistry and Mineralogy, Universität Leipzig, Deutscher Platz 5, 04103, Leipzig, Germany.|Center for Biotechnology and Biomedicine, Universität Leipzig, Deutscher Platz 5, 04103, Leipzig, Germany.
Ralf
R
Hoffmann
Karlsruhe Institute of Technology (KIT), Institute of Functional Interfaces and Institute of Microstructure Technology, P.O. Box 3640, 76021, Karlsruhe, Germany.|Institute of Infection and Immunity, St. George's, University of London, Cranmer Terrace, London, SW17 0RE, UK.
Kai
K
Hilpert
D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology*; D023181:Antimicrobial Cationic Peptides / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology*; D006801:Humans; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D015394:Molecular Structure; D011550:Pseudomonas aeruginosa / Q000187:drug effects / Q000254:growth & development; D013203:Staphylococcal Infections / Q000382:microbiology; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000254:growth & development
D000900:Anti-Bacterial Agents; D023181:Antimicrobial Cationic Peptides; C551620:oncocin
Oncocin; Proline-rich antimicrobial peptide; Pseudomonas aeruginosa; Quartz crystal microbalance; SPOT synthesis