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Membrane structure and conformational changes of the antibiotic heterodimeric peptide distinctin by solid-state NMR spectroscopy.

Abstract：

:The heterodimeric antimicrobial peptide distinctin is composed of 2 linear peptide chains of 22- and 25-aa residues that are connected by a single intermolecular S-S bond. This heterodimer has been considered to be a unique example of a previously unrecorded class of bioactive peptides. Here the 2 distinctin chains were prepared by chemical peptide synthesis in quantitative amounts and labeled with (15)N, as well as (15)N and (2)H, at selected residues, respectively, and the heterodimer was formed by oxidation. CD spectroscopy indicates a high content of helical secondary structures when associated with POPC/POPG 3:1 vesicles or in membrane-mimetic environments. The propensity for helix formation follows the order heterodimer >chain 2 >chain 1, suggesting that peptide-peptide and peptide-lipid interactions both help in stabilizing this secondary structure. In a subsequent step the peptides were reconstituted into oriented phospholipid bilayers and investigated by (2)H and proton-decoupled (15)N solid-state NMR spectroscopy. Whereas chain 2 stably inserts into the membrane at orientations close to perfectly parallel to the membrane surface in the presence or absence of chain 1, the latter adopts a more tilted alignment, which further increases in the heterodimer. The data suggest that membrane interactions result in considerable conformational rearrangements of the heterodimer. Therefore, chain 2 stably anchors the heterodimer in the membrane, whereas chain 1 interacts more loosely with the bilayer. These structural observations are consistent with the antimicrobial activities when the individual chains are compared to the dimer.

journal_name

Proc Natl Acad Sci U S A

journal_title

Proceedings of the National Academy of Sciences of the United States of America

authors

Resende JM,Moraes CM,Munhoz VH,Aisenbrey C,Verly RM,Bertani P,Cesar A,Piló-Veloso D,Bechinger B

doi

10.1073/pnas.0905069106

subject

Has Abstract

pub_date

2009-09-29 00:00:00

pages

16639-44

issue

eissn

0027-8424

issn

1091-6490

pii

0905069106

journal_volume

106

pub_type

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Membrane structure and conformational changes of the antibiotic heterodimeric peptide distinctin by solid-state NMR spectroscopy.