PDBsum entry 1ab6

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protein links
Chemotaxis PDB id
Protein chains
125 a.a. *
Waters ×41
* Residue conservation analysis
PDB id:
Name: Chemotaxis
Title: Structure of chey mutant f14n, v86t
Structure: Chemotaxis protein chey. Chain: a, b. Synonym: chey. Engineered: yes. Mutation: yes
Source: Escherichia coli. Organism_taxid: 562. Expressed in: escherichia coli. Expression_system_taxid: 562.
2.20Å     R-factor:   0.192     R-free:   0.280
Authors: D.Wilcock,M.T.Pisabarro,E.Lopez-Hernandez,L.Serranno,M.Coll
Key ref:
D.Wilcock et al. (1998). Structure analysis of two CheY mutants: importance of the hydrogen-bond contribution to protein stability. Acta Crystallogr D Biol Crystallogr, 54, 378-385. PubMed id: 9761905
04-Feb-97     Release date:   04-Feb-98    
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Protein chains
Pfam   ArchSchema ?
P0AE67  (CHEY_ECOLI) -  Chemotaxis protein CheY
129 a.a.
125 a.a.*
Key:    PfamA domain  Secondary structure  CATH domain
* PDB and UniProt seqs differ at 2 residue positions (black crosses)

 Gene Ontology (GO) functional annotation 
  GO annot!
  Cellular component     cytoplasm   1 term 
  Biological process     bacterial-type flagellar cell motility   6 terms 
  Biochemical function     protein binding     4 terms  


Acta Crystallogr D Biol Crystallogr 54:378-385 (1998)
PubMed id: 9761905  
Structure analysis of two CheY mutants: importance of the hydrogen-bond contribution to protein stability.
D.Wilcock, M.T.Pisabarro, E.López-Hernandez, L.Serrano, M.Coll.
The crystal structures of two double mutants (F14N/V21T and F14N/V86T) of the signal transduction protein CheY have been determined to a resolution of 2.4 and 2.2 A, respectively. The structures were solved by molecular replacement and refined to final R values of 18.4 and 19.2%, respectively. Together with urea-denaturation experiments the structures have been used to analyse the effects of mutations where hydrophobic residues are replaced by residues capable of establishing hydrogen bonds. The large increase in stabilization (-12.1 kJ mol-1) of the mutation Phe14Asn arises from two factors: a reverse hydrophobic effect and the formation of a good N-cap at alpha-helix 1. In addition, a forward-backward hydrogen-bonding pattern, resembling an N-capping box and involving Asn14 and Arg18, has been found. The two Val to Thr mutations at the hydrophobic core have different thermodynamic effects: the mutation Val21Thr does not affect the stability of the protein while the mutation Val86Thr causes a small destabilization of 1.7 kJ mol-1. At site 21 a backward side chain-to-backbone hydrogen bond is formed inside alpha-helix 1 with the carbonyl O atom of the i - 4 residue without movement of the mutated side chain. The destabilizing effect of introducing a polar group in the core is efficiently compensated for by the formation of an extra hydrogen bond. At site 86 the new Ogamma atom escapes from the hydrophobic environment by a chi1 rotation into an adjacent hydrophilic cavity to form a new hydrogen bond. In this case the isosteric Val to Thr substitution is disruptive but the loss in stabilization energy is partly compensated by the formation of a hydrogen bond. The two crystal structures described in this work underline the significance of the hydrogen-bond component to protein stability.

Literature references that cite this PDB file's key reference

  PubMed id Reference
11369848 P.Garcia, L.Serrano, D.Durand, M.Rico, and M.Bruix (2001).
NMR and SAXS characterization of the denatured state of the chemotactic protein CheY: implications for protein folding initiation.
  Protein Sci, 10, 1100-1112.  
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