1vm5
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(New page: 200px<br /><applet load="1vm5" size="450" color="white" frame="true" align="right" spinBox="true" caption="1vm5" /> '''Solution structure of micelle-bound aurein 1...)
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Revision as of 02:49, 21 November 2007
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Solution structure of micelle-bound aurein 1.2, an antimicrobial and anticancer peptide from an Australian frog
Overview
To understand the functional differences between a nontoxic membrane, anchor corresponding to the N-terminal sequence of the Escherichia coli, enzyme IIA(Glc) and a toxic antimicrobial peptide aurein 1.2 of similar, sequence, a series of peptides was designed to bridge the gap between, them. An alteration of a single residue of the membrane anchor converted, it into an antibacterial peptide. Circular dichroism spectra indicate that, all peptides are disordered in water but helical in micelles. Structures, of the peptides were determined in membrane-mimetic micelles by solution, NMR spectroscopy. The quality of the distance-based structures was, improved by including backbone angle restraints derived from a set of, chemical shifts ((1)H(alpha), (15)N, (13)C(alpha), and (13)C(beta)) from, natural abundance two-dimensional heteronuclear correlated spectroscopy., Different from the membrane anchor, antibacterial peptides possess a, broader and longer hydrophobic surface, allowing a deeper penetration into, the membrane, as supported by intermolecular nuclear Overhauser effect, cross-peaks between the peptide and short chain dioctanoyl, phosphatidylglycerol. An attempt was made to correlate the NMR structures, of these peptides with their antibacterial activity. The activity of this, group of peptides does not correlate exactly with helicity, amphipathicity, charge, the number of charges, the size of the hydrophobic, surface, or hydrophobic transfer free energy. However, a correlation is, established between the peptide activity and membrane perturbation, potential, which is defined by interfacial hydrophobic patches and basic, residues in the case of cationic peptides. Indeed, (31)P solid state NMR, spectroscopy of lipid bilayers showed that the extent of lipid vesicle, disruption by these peptides is proportional to their membrane, perturbation potential.
About this Structure
1VM5 is a Protein complex structure of sequences from [1] with NH2 as ligand. Full crystallographic information is available from OCA.
Reference
Correlation of three-dimensional structures with the antibacterial activity of a group of peptides designed based on a nontoxic bacterial membrane anchor., Wang G, Li Y, Li X, J Biol Chem. 2005 Feb 18;280(7):5803-11. Epub 2004 Nov 30. PMID:15572363
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