4GAD

Crystal Structure of D230A/H234A Mutant of Stationary Phase Survival Protein (SurE) from Salmonella typhimurium

Summary for 4GAD

• Entry DOI: 10.2210/pdb4gad/pdb
• Related: 2V4N 2V4O 4G9O
• Descriptor: 5'/3'-nucleotidase SurE, GLYCEROL, MAGNESIUM ION, ... (4 entities in total)
• Functional Keywords: stationary phase survival protein, domain swapping, rossmann fold, phosphatase, hydrolase
• Biological source: Salmonella typhimurium
• Cellular location: Cytoplasm (Potential): P66881
• Total number of polymer chains: 2
• Total formula weight: 57240.87

Authors

Mathiharan, Y.K.,Murthy, M.R.N. (deposition date: 2012-07-25, release date: 2013-03-13, Last modification date: 2023-11-08)

Primary citation

Mathiharan, Y.K.,Pappachan, A.,Savithri, H.S.,Murthy, M.R.N.
Dramatic Structural Changes Resulting from the Loss of a Crucial Hydrogen Bond in the Hinge Region Involved in C-Terminal Helix Swapping in SurE: A Survival Protein from Salmonella typhimurium.
Plos One, 8:e55978-e55978, 2013

PubMed Abstract: Domain swapping is an interesting feature of some oligomeric proteins in which each protomer of the oligomer provides an identical surface for exclusive interaction with a segment or domain belonging to another protomer. Here we report results of mutagenesis experiments on the structure of C-terminal helix swapped dimer of a stationary phase survival protein from Salmonella typhimurium (StSurE). Wild type StSurE is a dimer in which a large helical segment at the C-terminus and a tetramerization loop comprising two β strands are swapped between the protomers. Key residues in StSurE that might promote C-terminal helix swapping were identified by sequence and structural comparisons. Three mutants in which the helix swapping is likely to be avoided were constructed and expressed in E. coli. Three-dimensional X-ray crystal structures of the mutants H234A and D230A/H234A could be determined at 2.1 Å and 2.35 Å resolutions, respectively. Contrary to expectations, helix swapping was mostly retained in both the mutants. The loss of the crucial D230 OD2- H234 NE2 hydrogen bond (2.89 Å in the wild type structure) in the hinge region was compensated by new inter and intra-chain interactions. However, the two fold molecular symmetry was lost and there were large conformational changes throughout the polypeptide. In spite of these changes, the dimeric structure and an approximate tetrameric organization were retained, probably due to the interactions involving the tetramerization loop. Mutants were mostly functionally inactive, highlighting the importance of precise inter-subunit interactions for the symmetry and function of StSurE.

PubMed: 23409101
DOI: 10.1371/journal.pone.0055978

Experimental method

X-RAY DIFFRACTION (2.35 Å)