2QFL

Structure of SuhB: Inositol monophosphatase and extragenic suppressor from E. coli

Summary for 2QFL

• Entry DOI: 10.2210/pdb2qfl/pdb
• Related: 1AWB 1G0H 1LBV 2BJI 2CZI 2P3N
• Descriptor: Inositol-1-monophosphatase, ACETATE ION, ETHYL ACETATE, ... (4 entities in total)
• Functional Keywords: impase extragenic suppressor, dimerization, hydrolase
• Biological source: Escherichia coli
• Total number of polymer chains: 1
• Total formula weight: 29268.13

Authors

Wang, Y.,Stieglitz, K.A.,Bubunenko, M.,Court, D.,Stec, B.,Roberts, M.F. (deposition date: 2007-06-27, release date: 2007-07-24, Last modification date: 2024-04-03)

Primary citation

Wang, Y.,Stieglitz, K.A.,Bubunenko, M.,Court, D.L.,Stec, B.,Roberts, M.F.
The structure of the R184A mutant of the inositol monophosphatase encoded by suhB and implications for its functional interactions in Escherichia coli.
J.Biol.Chem., 282:26989-26996, 2007

PubMed Abstract: The Escherichia coli product of the suhB gene, SuhB, is an inositol monophosphatase (IMPase) that is best known as a suppressor of temperature-sensitive growth phenotypes in E. coli. To gain insights into these biological diverse effects, we determined the structure of the SuhB R184A mutant protein. The structure showed a dimer organization similar to other IMPases, but with an altered interface suggesting that the presence of Arg-184 in the wild-type protein could shift the monomer-dimer equilibrium toward monomer. In parallel, a gel shift assay showed that SuhB forms a tight complex with RNA polymerase (RNA pol) that inhibits the IMPase catalytic activity of SuhB. A variety of SuhB mutant proteins designed to stabilize the dimer interface did not show a clear correlation with the ability of a specific mutant protein to complement the DeltasuhB mutation when introduced extragenically despite being active IMPases. However, the loss of sensitivity to RNA pol binding, i.e. in G173V, R184I, and L96F/R184I, did correlate strongly with loss of complementation of DeltasuhB. Because residue 184 forms the core of the SuhB dimer, it is likely that the interaction with RNA polymerase requires monomeric SuhB. The exposure of specific residues facilitates the interaction of SuhB with RNA pol (or another target with a similar binding surface) and it is this heterodimer formation that is critical to the ability of SuhB to rescue temperature-sensitive phenotypes in E. coli.

PubMed: 17652087
DOI: 10.1074/jbc.M701210200

Experimental method

X-RAY DIFFRACTION (1.9 Å)