Crystal structures of EcYihV SF kinase.
(a) Kinetic
plots showing effect of metabolites on EcYihV-catalyzed phosphorylation
of SF to SFP at [ATP] = 1.0 mM. (b) (Left) EcYihV
dimer in complex with AMPPNP·Mg in open and closed conformations
is shown in ribbon with the two subunits shown in coral and blue.
Each subunit is composed of two-domain architecture with α/β
nucleotide binding domain and β-sheet “lid” domain.
(Right) Lid domains of the dimer form a β-clasp dimerization
motif that serves both structural and catalytic roles. (c) Close-up
view of EcYihV·AMPPNP·Mg showing nucleotide
binding site in the closed conformation. (d) EcYihV·SFP
complex structure and active site interactions with bound SFP product
molecule. (e) Close-up view of EcYihV·ADP·Mg·SF
active site showing hydrogen bonding interactions in a quaternary
complex. Backbone and carbon atoms of subunits A and B are shown in
coral and blue, respectively, and ADP, AMPPNP, SF, and SFP are shown
in cylinder format. Electron density corresponds to the 2Fo –
Fc and in blue at levels of 1σ for c–e. (f) Cartoon of
ligand binding pocket of EcYihV·ADP·Mg·SF
complex depicting hydrogen bonding interactions with active site residues.