Structural characterization of the full-Length response regulator spr1814 in complex with a phosphate analogue reveals a novel conformational plasticity of the linker region.
Spr1814 of Streptococcus pneumoniae is a response regulator (RR) that belongs to
the NarL/FixJ subfamily and has a four-helix helix-turn-helix DNA-binding
domain. Here, the X-ray crystal structure of the full-length spr1814 in complex
with a phosphate analogue beryllium fluoride (BeF3(-)) was determined at
2.0 Å. This allows for a structural comparison with the previously reported
full-length unphosphorylated spr1814. The phosphorylation of conserved aspartic
acid residue of N-terminal receiver domain triggers a structural perturbation at
the α4-β5-α5 interface, leading to the domain reorganization of spr1814, and
this is achieved by a rotational change in the C-terminal DNA-binding domain.
