1za8
From Proteopedia
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| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
NMR solution structure of a leaf-specific-expressed cyclotide vhl-1
Overview
Based on a newly established sequencing strategy featured by its efficiency, simplicity, and easy manipulation, the sequences of four novel cyclotides (macrocyclic knotted proteins) isolated from an Australian plant Viola hederaceae were determined. The three-dimensional solution structure of V. hederaceae leaf cyclotide-1 (vhl-1), a leaf-specific expressed 31-residue cyclotide, has been determined using two-dimensional (1)H NMR spectroscopy. vhl-1 adopts a compact and well defined structure including a distorted triple-stranded beta-sheet, a short 3(10) helical segment and several turns. It is stabilized by three disulfide bonds, which, together with backbone segments, form a cyclic cystine knot motif. The three-disulfide bonds are almost completely buried into the protein core, and the six cysteines contribute only 3.8% to the molecular surface. A pH titration experiment revealed that the folding of vhl-1 shows little pH dependence and allowed the pK(a) of 3.0 for Glu(3) and approximately 5.0 for Glu(14) to be determined. Met(7) was found to be oxidized in the native form, consistent with the fact that its side chain protrudes into the solvent, occupying 7.5% of the molecular surface. vhl-1 shows anti-HIV activity with an EC(50) value of 0.87 microm.
About this Structure
1ZA8 is a Protein complex structure of sequences from Viola hederacea. Full crystallographic information is available from OCA.
Reference
Isolation and characterization of novel cyclotides from Viola hederaceae: solution structure and anti-HIV activity of vhl-1, a leaf-specific expressed cyclotide., Chen B, Colgrave ML, Daly NL, Rosengren KJ, Gustafson KR, Craik DJ, J Biol Chem. 2005 Jun 10;280(23):22395-405. Epub 2005 Apr 11. PMID:15824119
Page seeded by OCA on Mon Mar 31 01:32:58 2008
