2E6C: Crystal Structure Of The Stationary Phase Survival Protein Sure From Thermus Thermophilus Hb8 Cocrystallized With Manganese And Amp

The stationary phase survival protein SurE is a metal ion-dependent phosphatase distributed among eubacteria, archaea, and eukaryotes. In Escherichia coli, SurE has activities as nucleotidase and exopolyphosphatase, and is thought to be involved in stress response. However, its physiological role and reaction mechanism are unclear. We report here the crystal structures of the tetramer of SurE from Thermus thermophilus HB8 (TtSurE) both alone and crystallized with Mn(2+) and substrate AMP. In the presence of Mn(2+) and AMP, differences between the protomers were observed in the active site and in the loop located near the active site; AMP-bound active sites with the loops in a novel open conformation were found in the two protomers, and AMP-free active sites with the loops in a conventional closed conformation were found in the other two protomers. The two loops in the open conformation are entwined with each other, and this entwining is suggested to be required for enzymatic activity by site-directed mutagenesis. TtSurE exists as an equilibrium mixture of dimer and tetramer in solution. The loop-entwined structure indicates that SurE acts as a tetramer. The structural features and the absence of negative cooperativity imply the half-of-the-sites reactivity mechanism resulting from a pre-existing tendency toward structural asymmetry.
PDB ID: 2E6CDownload
MMDB ID: 58697
PDB Deposition Date: 2006/12/26
Updated in MMDB: 2012/11
Experimental Method:
x-ray diffraction
Resolution: 2.05  Å
Source Organism:
Similar Structures:
Biological Unit for 2E6C: tetrameric; determined by author
Molecular Components in 2E6C
Label Count Molecule
Proteins (4 molecules)
5'-nucleotidase Sure(Gene symbol: TTHB070)
Molecule annotation
Chemicals (15 molecules)
* Click molecule labels to explore molecular sequence information.

Citing MMDB