Biophysical studies on the antimicrobial activity of linearized esculentin 2EM

Erum Malik; David A Phoenix; Kamal Badiani; Timothy J Snape; Frederick Harris; Jaipaul Singh; Leslie Hugh Glyn Morton; Sarah R Dennison

doi:10.1016/j.bbamem.2019.183141

Biophysical studies on the antimicrobial activity of linearized esculentin 2EM

Biochim Biophys Acta Biomembr. 2020 Feb 1;1862(2):183141. doi: 10.1016/j.bbamem.2019.183141. Epub 2019 Nov 29.

Authors

Erum Malik¹, David A Phoenix², Kamal Badiani³, Timothy J Snape⁴, Frederick Harris¹, Jaipaul Singh¹, Leslie Hugh Glyn Morton¹, Sarah R Dennison⁵

Affiliations

¹ School of Forensic and Applied Science, University of Central Lancashire, Preston PR1 2HE, UK.
² Office of the Vice Chancellor, London South Bank University, 103 Borough Road, London SE1 0AA, UK.
³ Pepceuticals Limited, 4 Feldspar Close, Warrens Park, Enderby, Leicestershire LE19 4JS, UK.
⁴ School of Pharmacy and Biological Sciences, University of Central Lancashire, Preston PR1 2HE, UK.
⁵ School of Pharmacy and Biological Sciences, University of Central Lancashire, Preston PR1 2HE, UK. Electronic address: srdennison1@uclan.ac.uk.

PMID: 31790693
DOI: 10.1016/j.bbamem.2019.183141

Abstract

Linearized esculentin 2 EM (E2EM-lin) from the frog, Glandirana emeljanovi was highly active against Gram-positive bacteria (minimum lethal concentration ≤ 5.0 μM) and strongly α-helical in the presence of lipid mimics of their membranes (>55.0%). The N-terminal α-helical structure adopted by E2EM-lin showed the potential to form a membrane interactive, tilted peptide with an hydrophobicity gradient over residues 9 to 23. E2EM-lin inserted strongly into lipid mimics of membranes from Gram-positive bacteria (maximal surface pressure changes ≥5.5 mN m^-¹), inducing increased rigidity (C_s^-¹ ↑), thermodynamic instability (ΔG_mix < 0 → ΔG_mix > 0) and high levels of lysis (>50.0%). These effects appeared to be driven by the high anionic lipid content of membranes from Gram-positive bacteria; namely phosphatidylglycerol (PG) and cardiolipin (CL) species. The high levels of α-helicity (60.0%), interaction (maximal surface pressure change = 6.7 mN m^-¹) and lysis (66.0%) shown by E2EM-lin with PG species was a major driver in the ability of the peptide to lyse and kill Gram-positive bacteria. E2EM-lin also showed high levels of α-helicity (62.0%) with CL species but only low levels of interaction (maximal surface pressure change = 2.9 mN m^-¹) and lysis (21.0%) with the lipid. These combined data suggest that E2EM-lin has a specificity for killing Gram-positive bacteria that involves the formation of tilted structure and appears to be primarily driven by PG-mediated membranolysis. These structure/function relationships are used to help explain the pore forming process proposed to describe the membranolytic, antibacterial action of E2EM-lin.

Keywords: Gram-positive bacteria; Linearized esculentin 2EM; Phosphatidylglycerol and cardiolipin; Tilted peptide; α-Helical structure.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Amphibian Proteins / chemistry*
Amphibian Proteins / pharmacology
Antimicrobial Cationic Peptides / chemistry*
Antimicrobial Cationic Peptides / pharmacology
Cell Membrane / drug effects
Gram-Negative Bacteria / drug effects
Gram-Positive Bacteria / drug effects
Protein Binding
Protein Conformation, alpha-Helical

Substances

Amphibian Proteins
Antimicrobial Cationic Peptides
esculentin-2EM peptide, Glandirama emeljanovi