2o0s
From Proteopedia
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LPS-bound structure of a designed peptide
Overview
Designing peptides that would interact with lipopolysaccharides (LPS) and, acquire a specific folded conformation can generate useful structural, insights toward the development of anti-sepsis agents. In this work, we, have constructed a 12-residue linear peptide, YW12, rich in aromatic and, aliphatic amino acid residues with a centrally located stretch of four, consecutive positively charged (KRKR) residues. In absence of LPS, YW12 is, predominantly unstructured in aqueous solution. Using transferred nuclear, Overhauser effect (Tr-NOE) spectroscopy, we demonstrate that YW12 adopts a, well-folded structure as a complex with LPS. Structure calculations reveal, that YW12 assumes an extended conformation at the N-terminus followed by, two consecutive beta-turns at its C-terminus. A hydrophobic core is formed, by extensive packing between number of aromatic and nonpolar residues, whereas the positively charged residues are segregated out to a separate, region essentially stabilizing an amphipathic structure. In an in vitro, LPS neutralization assay using NF-kappaB induction as the readout, YW12, shows moderate activity with an IC50 value of approximately 10 muM. As, would be expected, tryptophan fluorescence studies demonstrate that YW12, shows selective interactions only with the negatively charged lipid, micelles including sodium dodecyl sulfate (SDS), 1-palmitoyl-2-oleoylphosphatidyl-dl-glycerol (POPG), and LPS, and no, significant interactions are detected with zwitterionic lipid micelles, such as dodecyl-phosphocholine (DPC). Far-UV CD studies indicate the, presence of beta-turns or beta-sheet-like conformations of the peptide in, negatively charged micelles, whereas no structural transitions are, apparent in DPC micelles. These results suggest that structural features, of YW12 could be utilized to develop nontoxic antisepsis compounds.
About this Structure
2O0S is a Protein complex structure of sequences from [1]. Full crystallographic information is available from OCA.
Reference
High-Resolution Solution Structure of a Designed Peptide Bound to Lipopolysaccharide: Transferred Nuclear Overhauser Effects, Micelle Selectivity, and Anti-Endotoxic Activity(,)., Bhattacharjya S, Domadia PN, Bhunia A, Malladi S, David SA, Biochemistry. 2007 May 22;46(20):5864-5874. Epub 2007 May 1. PMID:17469802
Page seeded by OCA on Wed Jan 23 15:03:45 2008
