2KUX

Solution structure of the cyclotide kalata B5 from Oldenlandia affinis


Experimental Data Snapshot

  • Method: SOLUTION NMR
  • Conformers Calculated: 50 
  • Conformers Submitted: 20 
  • Selection Criteria: structures with the lowest energy 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Structural and biochemical characteristics of the cyclotide kalata B5 from Oldenlandia affinis

Plan, M.R.Rosengren, K.J.Sando, L.Daly, N.L.Craik, D.J.

(2010) Biopolymers 94: 647-658

  • DOI: 10.1002/bip.21409

  • PubMed Abstract: 
  • Cyclotides are a large family of plant-derived proteins typified by their head-to-tail cyclic backbone and knotted arrangement of three disulfide bonds. Although they display a diverse range of biological activities, their native function is thought ...

    Cyclotides are a large family of plant-derived proteins typified by their head-to-tail cyclic backbone and knotted arrangement of three disulfide bonds. Although they display a diverse range of biological activities, their native function is thought to be plant defense. Here we characterized the expression, three-dimensional structure, and hemolytic activity of the cyclotide kalata B5 from the African plant Oldenlandia affinis. Kalata B5 shows an interesting seasonal variation in its expression and can only be isolated during certain times of the year, when the plant is flowering. It displays a typical tightly folded cyclic Scystine knot structure. A range of pH and temperature titrations reveal that a conserved glutamic acid in loop 1 Sof the structure forms a key hydrogen bond network, similar to that reported previously for other cyclotides. However, specific line broadening in the NMR spectra of kalata B5 suggests that the hydrogen bonding network in this peptide is less rigid than in other cyclotides. Notably, the pK9a) of Glu6 of 4.5 is higher than the values for other cyclotides studied so far, which range from 3.0 to 4.0, providing a further indication of a weaker hydrogen bond network. Kalata B5 has only moderate hemolytic activity compared with other highly expressed cyclotides, and this reduced activity probably reflects its more flexible structure. As is the case with other cyclotides, kalata B5 has an exposed hydrophobic region on its surface, supporting suggestions that this hydrophobic patch is a key feature for membrane binding and biological activity of cyclotides.


    Organizational Affiliation

    Institute for Molecular Bioscience, Division of Chemistry and Structural Biology, The University of Queensland, 306 Carmody Rd, St. Lucia, QLD 4067, Australia.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Kalata-B5
A
30Oldenlandia affinisMutation(s): 0 
Find proteins for P58456 (Oldenlandia affinis)
Go to UniProtKB:  P58456
Experimental Data & Validation

Experimental Data

  • Method: SOLUTION NMR
  • Conformers Calculated: 50 
  • Conformers Submitted: 20 
  • Selection Criteria: structures with the lowest energy 
  • Olderado: 2KUX Olderado

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2010-03-23
    Type: Initial release
  • Version 1.1: 2011-07-13
    Type: Version format compliance
  • Version 1.2: 2016-06-01
    Type: Database references