 |
PDBsum entry 4xep
|
|
|
|
References listed in PDB file
|
 |
|
Key reference
|
|
|
Title
|
|
Insights into stabilizing interactions in the distorted domain-Swapped dimer of salmonella typhimurium survival protein.
|
|
|
Authors
|
|
Y.K.Mathiharan,
H.S.Savithri,
M.R.Murthy.
|
|
|
Ref.
|
|
Acta Crystallogr D Biol Crystallogr, 2015,
71,
1812-1823.
[DOI no: ]
|
|
|
PubMed id
|
|
|
|
|
|
Abstract
|
|
|
The survival protein SurE from Salmonella typhimurium (StSurE) is a dimeric
protein that functions as a phosphatase. SurE dimers are formed by the swapping
of a loop with a pair of β-strands and a C-terminal helix between two
protomers. In a previous study, the Asp230 and His234 residues were mutated to
Ala to abolish a hydrogen bond that was thought to be crucial for C-terminal
helix swapping. These mutations led to functionally inactive and distorted
dimers in which the two protomers were related by a rotation of 167°. New salt
bridges involving Glu112 were observed in the dimeric interface of the H234A and
D230A/H234A mutants. To explore the role of these salt bridges in the stability
of the distorted structure, E112A, E112A/D230A, E112A/H234A, E112A/D230A/H234A,
R179L/H180A/H234A and E112A/R179L/H180A/H234A mutants were constructed. X-ray
crystal structures of the E112A, E112A/H234A and E112A/D230A mutants could be
determined. The dimeric structures of the E112A and E112A/H234A mutants were
similar to that of native SurE, while the E112A/D230A mutant had a residual
rotation of 11° between the B chains upon superposition of the A chains of the
mutant and native dimers. The native dimeric structure was nearly restored in
the E112A/H234A mutant, suggesting that the new salt bridge observed in the
H234A and D230A/H234A mutants was indeed responsible for the stability of their
distorted structures. Catalytic activity was also restored in these mutants,
implying that appropriate dimeric organization is necessary for the activity of
SurE.
|
|
|
|
|
|
|
