NMR Structure of Temporin-1 Ta in Lipopolysaccharide Micelles: Mechanistic Insight into Inactivation by Outer Membrane

BACKGROUND: Antimicrobial peptides (AMPs) play important roles in the innate defense mechanism. The broad spectrum of activity of AMPs requires an efficient permeabilization of the bacterial outer and inner membranes. The outer leaflet of the outer membrane of Gram negative bacteria is made of a spe...

Descripción completa

Detalles Bibliográficos
Autores principales: Saravanan, Rathi, Joshi, Mangesh, Mohanram, Harini, Bhunia, Anirban, Mangoni, Maria Luisa, Bhattacharjya, Surajit
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2013
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3767682/
https://www.ncbi.nlm.nih.gov/pubmed/24039798
http://dx.doi.org/10.1371/journal.pone.0072718
_version_ 1782283688514420736
author Saravanan, Rathi
Joshi, Mangesh
Mohanram, Harini
Bhunia, Anirban
Mangoni, Maria Luisa
Bhattacharjya, Surajit
author_facet Saravanan, Rathi
Joshi, Mangesh
Mohanram, Harini
Bhunia, Anirban
Mangoni, Maria Luisa
Bhattacharjya, Surajit
author_sort Saravanan, Rathi
collection PubMed
description BACKGROUND: Antimicrobial peptides (AMPs) play important roles in the innate defense mechanism. The broad spectrum of activity of AMPs requires an efficient permeabilization of the bacterial outer and inner membranes. The outer leaflet of the outer membrane of Gram negative bacteria is made of a specialized lipid called lipopolysaccharide (LPS). The LPS layer is an efficient permeability barrier against anti-bacterial agents including AMPs. As a mode of protection, LPS can induce self associations of AMPs rendering them inactive. Temporins are a group of short-sized AMPs isolated from frog skin, and many of them are inactive against Gram negative bacteria as a result of their self-association in the LPS-outer membrane. PRINCIPAL FINDINGS: Using NMR spectroscopy, we have determined atomic resolution structure and characterized localization of temporin-1Ta or TA (FLPLIGRVLSGIL-amide) in LPS micelles. In LPS micelles, TA adopts helical conformation for residues L4-I12, while residues F1-L3 are found to be in extended conformations. The aromatic sidechain of residue F1 is involved in extensive packing interactions with the sidechains of residues P3, L4 and I5. Interestingly, a number of long-range NOE contacts have been detected between the N-terminal residues F1, P3 with the C-terminal residues S10, I12, L13 of TA in LPS micelles. Saturation transfer difference (STD) NMR studies demonstrate close proximity of residues including F1, L2, P3, R7, S10 and L13 with the LPS micelles. Notably, the LPS bound structure of TA shows differences with the structures of TA determined in DPC and SDS detergent micelles. SIGNIFICANCE: We propose that TA, in LPS lipids, forms helical oligomeric structures employing N- and C-termini residues. Such oligomeric structures may not be translocated across the outer membrane; resulting in the inactivation of the AMP. Importantly, the results of our studies will be useful for the development of antimicrobial agents with a broader spectrum of activity.
format Online
Article
Text
id pubmed-3767682
institution National Center for Biotechnology Information
language English
publishDate 2013
publisher Public Library of Science
record_format MEDLINE/PubMed
spelling pubmed-37676822013-09-13 NMR Structure of Temporin-1 Ta in Lipopolysaccharide Micelles: Mechanistic Insight into Inactivation by Outer Membrane Saravanan, Rathi Joshi, Mangesh Mohanram, Harini Bhunia, Anirban Mangoni, Maria Luisa Bhattacharjya, Surajit PLoS One Research Article BACKGROUND: Antimicrobial peptides (AMPs) play important roles in the innate defense mechanism. The broad spectrum of activity of AMPs requires an efficient permeabilization of the bacterial outer and inner membranes. The outer leaflet of the outer membrane of Gram negative bacteria is made of a specialized lipid called lipopolysaccharide (LPS). The LPS layer is an efficient permeability barrier against anti-bacterial agents including AMPs. As a mode of protection, LPS can induce self associations of AMPs rendering them inactive. Temporins are a group of short-sized AMPs isolated from frog skin, and many of them are inactive against Gram negative bacteria as a result of their self-association in the LPS-outer membrane. PRINCIPAL FINDINGS: Using NMR spectroscopy, we have determined atomic resolution structure and characterized localization of temporin-1Ta or TA (FLPLIGRVLSGIL-amide) in LPS micelles. In LPS micelles, TA adopts helical conformation for residues L4-I12, while residues F1-L3 are found to be in extended conformations. The aromatic sidechain of residue F1 is involved in extensive packing interactions with the sidechains of residues P3, L4 and I5. Interestingly, a number of long-range NOE contacts have been detected between the N-terminal residues F1, P3 with the C-terminal residues S10, I12, L13 of TA in LPS micelles. Saturation transfer difference (STD) NMR studies demonstrate close proximity of residues including F1, L2, P3, R7, S10 and L13 with the LPS micelles. Notably, the LPS bound structure of TA shows differences with the structures of TA determined in DPC and SDS detergent micelles. SIGNIFICANCE: We propose that TA, in LPS lipids, forms helical oligomeric structures employing N- and C-termini residues. Such oligomeric structures may not be translocated across the outer membrane; resulting in the inactivation of the AMP. Importantly, the results of our studies will be useful for the development of antimicrobial agents with a broader spectrum of activity. Public Library of Science 2013-09-09 /pmc/articles/PMC3767682/ /pubmed/24039798 http://dx.doi.org/10.1371/journal.pone.0072718 Text en © 2013 Saravanan et al http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited.
spellingShingle Research Article
Saravanan, Rathi
Joshi, Mangesh
Mohanram, Harini
Bhunia, Anirban
Mangoni, Maria Luisa
Bhattacharjya, Surajit
NMR Structure of Temporin-1 Ta in Lipopolysaccharide Micelles: Mechanistic Insight into Inactivation by Outer Membrane
title NMR Structure of Temporin-1 Ta in Lipopolysaccharide Micelles: Mechanistic Insight into Inactivation by Outer Membrane
title_full NMR Structure of Temporin-1 Ta in Lipopolysaccharide Micelles: Mechanistic Insight into Inactivation by Outer Membrane
title_fullStr NMR Structure of Temporin-1 Ta in Lipopolysaccharide Micelles: Mechanistic Insight into Inactivation by Outer Membrane
title_full_unstemmed NMR Structure of Temporin-1 Ta in Lipopolysaccharide Micelles: Mechanistic Insight into Inactivation by Outer Membrane
title_short NMR Structure of Temporin-1 Ta in Lipopolysaccharide Micelles: Mechanistic Insight into Inactivation by Outer Membrane
title_sort nmr structure of temporin-1 ta in lipopolysaccharide micelles: mechanistic insight into inactivation by outer membrane
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3767682/
https://www.ncbi.nlm.nih.gov/pubmed/24039798
http://dx.doi.org/10.1371/journal.pone.0072718
work_keys_str_mv AT saravananrathi nmrstructureoftemporin1tainlipopolysaccharidemicellesmechanisticinsightintoinactivationbyoutermembrane
AT joshimangesh nmrstructureoftemporin1tainlipopolysaccharidemicellesmechanisticinsightintoinactivationbyoutermembrane
AT mohanramharini nmrstructureoftemporin1tainlipopolysaccharidemicellesmechanisticinsightintoinactivationbyoutermembrane
AT bhuniaanirban nmrstructureoftemporin1tainlipopolysaccharidemicellesmechanisticinsightintoinactivationbyoutermembrane
AT mangonimarialuisa nmrstructureoftemporin1tainlipopolysaccharidemicellesmechanisticinsightintoinactivationbyoutermembrane
AT bhattacharjyasurajit nmrstructureoftemporin1tainlipopolysaccharidemicellesmechanisticinsightintoinactivationbyoutermembrane