1KV0

Cis/trans Isomerization of Non-prolyl Peptide Bond Observed in Crystal Structure of an Scorpion Toxin


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.4 Å
  • R-Value Free: 0.164 
  • R-Value Work: 0.142 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Structural mechanism governing cis and trans isomeric states and an intramolecular switch for cis/trans isomerization of a non-proline peptide bond observed in crystal structures of scorpion toxins.

Guan, R.J.Xiang, Y.He, X.L.Wang, C.G.Wang, M.Zhang, Y.Sundberg, E.J.Wang, D.C.

(2004) J.Mol.Biol. 341: 1189-1204

  • DOI: 10.1016/j.jmb.2004.06.067
  • Primary Citation of Related Structures:  1T7A, 1T7B, 1T7E

  • PubMed Abstract: 
  • Non-proline cis peptide bonds have been observed in numerous protein crystal structures even though the energetic barrier to this conformation is significant and no non-prolyl-cis/trans-isomerase has been identified to date. While some external facto ...

    Non-proline cis peptide bonds have been observed in numerous protein crystal structures even though the energetic barrier to this conformation is significant and no non-prolyl-cis/trans-isomerase has been identified to date. While some external factors, such as metal binding or co-factor interaction, have been identified that appear to induce cis/trans isomerization of non-proline peptide bonds, the intrinsic structural basis for their existence and the mechanism governing cis/trans isomerization in proteins remains poorly understood. Here, we report the crystal structure of a newly isolated neurotoxin, the scorpion alpha-like toxin Buthus martensii Karsch (BmK) M7, at 1.4A resolution. BmK M7 crystallizes as a dimer in which the identical non-proline peptide bond between residues 9 and 10 exists either in the cis conformation or as a mixture of cis and trans conformations in either monomer. We also determined the crystal structures of several mutants of BmK M1, a representative scorpion alpha-like toxin that contains an identical non-proline cis peptide bond as that observed in BmK M7, in which residues within or neighboring the cis peptide bond were altered. Substitution of an aspartic acid residue for lysine at residue 8 in the BmK M1 (K8D) mutant converted the cis form of the non-proline peptide bond 9-10 into the trans form, revealing an intramolecular switch for cis-to-trans isomerization. Cis/trans interconversion of the switch residue at position 8 appears to be sequence-dependent as the peptide bond between residues 9 and 10 retains its wild-type cis conformation in the BmK M1 (K8Q) mutant structure. The structural interconversion of the isomeric states of the BmK M1 non-proline cis peptide bond may relate to the conversion of the scorpion alpha-toxins subgroups.


    Organizational Affiliation

    Center for Structural and Molecular Biology, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, People's Republic of China.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Alpha-like toxin BmK-M7
A, B
66Mesobuthus martensiiN/A
Find proteins for P59854 (Mesobuthus martensii)
Go to UniProtKB:  P59854
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.4 Å
  • R-Value Free: 0.164 
  • R-Value Work: 0.142 
  • Space Group: P 31 2 1
Unit Cell:
Length (Å)Angle (°)
a = 32.758α = 90.00
b = 32.758β = 90.00
c = 176.822γ = 120.00
Software Package:
Software NamePurpose
AMoREphasing
MOSFLMdata reduction
SCALAdata scaling
REFMACrefinement
CCP4data scaling

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2003-09-16
    Type: Initial release
  • Version 1.1: 2008-01-04
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance