1ZA8

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

Summary for 1ZA8

• Entry DOI: 10.2210/pdb1za8/pdb
• NMR Information: BMRB: 6596
• Descriptor: vhl-1 (1 entity in total)
• Functional Keywords: circular protein, cyclic cystine knot motif, antiviral protein
• Biological source: Viola hederacea
• Total number of polymer chains: 1
• Total formula weight: 3342.95

Authors

Chen, B.,Colgrave, M.L.,Daly, N.L.,Rosengren, K.J.,Gustafson, K.R.,Craik, D.J. (deposition date: 2005-04-05, release date: 2005-04-12, Last modification date: 2024-10-23)

Primary citation

Chen, B.,Colgrave, M.L.,Daly, N.L.,Rosengren, K.J.,Gustafson, K.R.,Craik, D.J.
Isolation and characterization of novel cyclotides from Viola hederaceae: solution structure and anti-HIV activity of vhl-1, a leaf-specific expressed cyclotide.
J.Biol.Chem., 280:22395-22405, 2005

PubMed Abstract: 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.

PubMed: 15824119
DOI: 10.1074/jbc.M501737200

Experimental method

SOLUTION NMR