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Figure 4.
Figure 4 X-ray structures of GlnK1 (A) in the absence of added
nucleotide at 2.1 Å; (B) with bound Mg-ATP at 1.2 Å;
(C) with Mg-ATP and 2-KG at 1.6 Å resolution. On the left
is the trimer with the Amt1 interaction surface facing up.
Individual protein monomers are drawn as blue, green and gray
ribbon diagrams. Bound cofactors are shown as ball-and-stick
models. In (A), one out of three monomers binds ADP; in (B), all
three monomers bind Mg-ATP; in (C), all three monomers bind ATP,
but only the blue monomer binds Mg^2+ as well, plus a single
molecule of 2-KG. The center of the trimer holds either an
acetate (A) or a chloride ion (yellow sphere). The corresponding
monomer side views are shown on the right. (A) Superposition of
six monomers with resolved T-loops in the extended conformation
(Supplementary Figure 4). (B) Superposition of three monomers of
one Mg-ATP-binding trimer, with T-loops in the compact
conformation. Color coding as in Supplementary Figures 3 and 4.
(C) Single monomer binding Mg-ATP and 2-KG.
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