1za8

NMR solution structure of a leaf-specific-expressed cyclotide vhl-1

spinqualitylabelsall models 1za8, 20 NMR models Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1za8 is a 1 chain structure with sequence from Viola hederacea. Full experimental information is available from OCA. For a guided tour on the structure components use FirstGlance. Resources: FirstGlance, OCA, RCSB, PDBsum Publication Abstract from PubMed 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. 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 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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