PDBsum entry 1m5t

Signaling protein, cell cycle

PDB id: 1m5t

Contents

Protein chain

123 a.a. *

Waters ×120

* Residue conservation analysis

PDB id:

1m5t

Name:

Signaling protein, cell cycle

Title:

Crystal structure of the response regulator divk

Structure:

Cell division response regulator divk. Chain: a. Synonym: polar differentiation response regulator. Chey homolog divk. Engineered: yes. Other_details: structure at ph 6.0 in the apo-form

Source:

Caulobacter vibrioides. Organism_taxid: 155892. Gene: divk. Expressed in: escherichia coli. Expression_system_taxid: 562.

Resolution:

1.60Å R-factor: 0.193 R-free: 0.213

Authors:

V.Guillet,N.Ohta,S.Cabantous,A.Newton,J.-P.Samama,Structural Proteomics In Europe (Spine)

Key ref:

V.Guillet et al. (2002). Crystallographic and biochemical studies of DivK reveal novel features of an essential response regulator in Caulobacter crescentus. J Biol Chem, 277, 42003-42010. PubMed id: 12176983 DOI: 10.1074/jbc.M204789200

Date:

10-Jul-02 Release date: 15-Nov-02

Protein chain

Q9A5I4  (Q9A5I4_CAUVC) -  Polar differentiation response regulator from Caulobacter vibrioides (strain ATCC 19089 / CB15)

Seq: 130 a.a.

Struc: 123 a.a.

Enzyme reactions

• Enzyme class: E.C.?

DOI no: 10.1074/jbc.M204789200

J Biol Chem 277:42003-42010 (2002)

PubMed id: 12176983

Crystallographic and biochemical studies of DivK reveal novel features of an essential response regulator in Caulobacter crescentus.

V.Guillet, N.Ohta, S.Cabantous, A.Newton, J.P.Samama.

ABSTRACT

DivK is an essential response regulator in the Gram-negative bacterium Caulobacter crescentus and functions in a complex phosphorelay system that precisely controls the sequence of developmental events during the cell division cycle. Structure determinations of this single domain response regulator at different pH values demonstrated that the five-stranded alpha/beta fold of the DivK protein is fully defined only at acidic pH. The crystal structures of the apoprotein and of metal-bound DivK complexes at higher pH values revealed a synergistic pH- and cation binding-induced flexibility of the beta4-alpha4 loop and of the alpha4 helix. This motion increases the solvent accessibility of the single cysteine residue in the protein. Solution state studies demonstrated a 200-fold pH-dependent increase in the affinity of manganese for the protein between pH 6.0 and 8.5 that seems to involve deprotonation of an acido-basic couple. Taken together, these results suggest that flexibility of critical regions of the protein, ionization of the cysteine 99 residue and improved K(D) values for the catalytic metal ion are coupled events. We propose that the molecular events observed in the isolated protein may be required for DivK activation and that they may be achieved in vivo through the specific protein-protein interactions between the response regulator and its cognate kinases.

Selected figure(s)

Figure 4.
Fig. 4. Stereoview of the 2F[o] F[c] electron density map in the active site region for the Mn2+-DivK complex at pH 8.0.

Figure 6.
Fig. 6. CA representation of the DivK structure illustrating by dotted line the non visible region (residues 84-97) when the metal binds with high affinity.

The above figures are reprinted by permission from the ASBMB: J Biol Chem (2002, 277, 42003-42010) copyright 2002.

Figures were selected by an automated process.