PDBsum entry 1m5t

Signaling protein, cell cycle

PDB id: 1m5t

Contents

Protein chain

123 a.a. *

Waters ×120

* Residue conservation analysis

References listed in PDB file

Key reference

Title

Crystallographic and biochemical studies of divk reveal novel features of an essential response regulator in caulobacter crescentus.

Authors

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

Ref.

J Biol Chem, 2002, 277, 42003-42010. [DOI no: 10.1074/jbc.M204789200]

PubMed id

12176983

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.

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.

Secondary reference #1

Title

Characterization and crystallization of divk, An essential response regulator for cell division and differentiation in caulobacter crescentus.

Authors

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

Ref.

Acta Crystallogr D Biol Crystallogr, 2002, 58, 1249-1251. [DOI no: 10.1107/S0907444902008338]

PubMed id

12077459

Figure 1.
Figure 1 Guinier representation of the scattering data measured at a protein concentration of 5 mg ml-1. Black squares, 20 mM MES, 25 mM NaCl pH 6; green diamonds, 20 mM MES pH 6; red triangles, 20 mM Tris, 50 mM NaCl pH 7; blue circles, 20 mM Tris, 50 mM NaCl pH 8.

The above figure is reproduced from the cited reference with permission from the IUCr

Secondary reference #2

Title

An essential single domain response regulator required for normal cell division and differentiation in caulobacter crescentus.

Authors

G.B.Hecht, T.Lane, N.Ohta, J.M.Sommer, A.Newton.

Ref.

Embo J, 1995, 14, 3915-3924.

PubMed id

7664732