Human‐β‐defensins‐1‐3 and analogs do not require proton motive force for antibacterial activity against Escherichia coli. Issue 1 (16th September 2013)

• Record Type: Journal Article
• Authors: Krishnakumari, Viswanatha; Packiyanathan, Kavin K.; Nagaraj, Ramakrishnan
• Is Part Of: FEMS microbiology letters. Volume 348:Issue 1(2013:Nov.)
• Page Start: 52
• Page End: 57
• Publication Date: 2013-09-16
• Subjects: Microbiology -- Periodicals; 579
• DOI: 10.1111/1574-6968.12242
• Languages: English
• ISSNs: 0378-1097

Abstract

<abstract abstract-type="main" id="fml12242-abs-0001"> <title>Abstract</title> <p>Human‐β‐defensins 1‐3 (HBD‐1‐3) and their C‐terminal analogs Phd‐1‐3 do not show antibacterial activity against <italic>Escherichia coli</italic> in the presence of mono‐ and divalent cations. Activity of peptides was examined against <italic>E. coli</italic> pretreated with carbonyl cyanide m‐chlorophenylhydrazone (CCCP) and salt remedial <italic>Escherichia coli ftsEX, </italic> a deletion mutant of FtsEX complex [an ATP‐binding cassette (ABC) transporter protein], in the presence of Na⁺, Ca²⁺, and Mg²⁺. Activity was observed in the presence of Na⁺ and Ca²⁺_, although not in the presence of Mg²⁺ against <italic>E. coli, </italic> when proton motive force (PMF) was dissipated by CCCP. The peptides exhibited antibacterial activity against <italic>E. coli ftsEX</italic> even in the presence of Na⁺ and Ca²⁺. Our results indicate that HBD‐1‐3 and Phd‐1‐3 do not require PMF for their antibacterial activity. The absence of activity against <italic>E. coli</italic> in the presence of Na⁺ and Ca²⁺ ions is due to not only weakened electrostatic interactions with anionic membrane components, but also involvement of electrochemical gradients. However, Mg²⁺ prevents electrostatic interaction of the peptides with the outer membrane resulting in loss of activity.</p> </abstract>