PDBsum entry: 1d5w

Gene regulation

PDB id: 1d5w

Contents

Protein chains

123 a.a. *

Ligands

SO4 ×4

Waters ×144

* Residue conservation analysis

PDB id:

1d5w

Name:

Gene regulation

Title:

Phosphorylated fixj receiver domain

Structure:

Transcriptional regulatory protein fixj. Chain: a, b, c. Fragment: fixj receiver domain (residues 1-126). Engineered: yes. Mutation: yes

Source:

Sinorhizobium meliloti. Organism_taxid: 382. Expressed in: escherichia coli. Expression_system_taxid: 562.

Biol. unit:

Hexamer (from PDB file)

Resolution:

2.30Å R-factor: 0.217 R-free: 0.244

Authors:

C.Birck,L.Mourey,P.Gouet,B.Fabry,J.Schumacher,P.Rousseau, D.Kahn,J.P.Samama

Key ref:

C.Birck et al. (1999). Conformational changes induced by phosphorylation of the FixJ receiver domain. Structure, 7, 1505-1515. PubMed id: 10647181 DOI: 10.1016/S0969-2126(00)88341-0

Date:

12-Oct-99 Release date: 11-Oct-00

Protein chains

P10958  (FIXJ_RHIME) -  Transcriptional regulatory protein fixJ

Seq: 204 a.a.

Struc: 123 a.a.*

* PDB and UniProt seqs differ at 2 residue positions (black crosses)

 Gene Ontology (GO) functional annotation 

• Biological process: two-component signal transduction system (phosphorelay) (2 terms)
• Biochemical function: two-component response regulator activity (1 term)

DOI no: 10.1016/S0969-2126(00)88341-0

Structure 7:1505-1515 (1999)

PubMed id: 10647181

Conformational changes induced by phosphorylation of the FixJ receiver domain.

C.Birck, L.Mourey, P.Gouet, B.Fabry, J.Schumacher, P.Rousseau, D.Kahn, J.P.Samama.

ABSTRACT

BACKGROUND: A variety of bacterial adaptative cellular responses to environmental stimuli are mediated by two-component signal transduction pathways. In these phosphorelay cascades, histidine kinases transphosphorylate a conserved aspartate in the receiver domain, a conserved module in the response regulator superfamily. The main effect of this phosphorylation is to alter the conformation of the response regulator in order to modulate its biological function. The response regulator FixJ displays a typical modular arrangement, with a phosphorylatable N-terminal receiver domain and a C-terminal DNA-binding domain. In the symbiotic bacterium Sinorhizobium meliloti, phosphorylation of this response regulator activates transcription of nitrogen-fixation genes. RESULTS: The crystal structures of the phosphorylated and of the unphosphorylated N-terminal receiver domain of FixJ (FixJN) were solved at 2.3 A and 2.4 A resolution, respectively. They reveal the environment of the phosphoaspartate in the active site and the specific conformational changes leading to activation of the response regulator. Phosphorylation of the conserved aspartate induces major structural changes in the beta 4-alpha 4 loop, and in the signaling surface alpha 4-beta 5 that mediates dimerization of the phosphorylated full-length response regulator. A site-directed mutant at this protein-protein interface decreases the affinity of the phosphorylated response regulator for the fixK promoter tenfold. CONCLUSIONS: The cascade of phosphorylation-induced conformational changes in FixJN illustrates the role of conserved residues in stabilizing the phosphoryl group in the active site, triggering the structural transition and achieving the post-phosphorylation signaling events. We propose that these phosphorylation-induced conformational changes underly the activation of response regulators in general.

Selected figure(s)

Figure 2.
Figure 2. View of the phosphorylated FixJN dimer. Each protomer is represented by ribbons and the color varies from dark blue (N terminus) to green (C terminus). The secondary structure elements are labeled and the phosphoaspartate groups are shown as spheres. The van der Waals surface of the dimer generated using SURFNET [58] is shown as a transparent solid.

The above figure is reprinted by permission from Cell Press: Structure (1999, 7, 1505-1515) copyright 1999.

Figure was selected by an automated process.