1mb0
From Proteopedia
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CRYSTAL STRUCTURE OF THE RESPONSE REGULATOR DIVK AT PH 8.0 IN COMPLEX WITH MN2+
Overview
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.
About this Structure
1MB0 is a Single protein structure of sequence from Caulobacter vibrioides with MN as ligand. Full crystallographic information is available from OCA.
Reference
Crystallographic and biochemical studies of DivK reveal novel features of an essential response regulator in Caulobacter crescentus., Guillet V, Ohta N, Cabantous S, Newton A, Samama JP, J Biol Chem. 2002 Nov 1;277(44):42003-10. Epub 2002 Aug 10. PMID:12176983
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