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Figure 1.
Fig. 1. Bacterial GatCAB complex fastens a molecular belt. (A)
Front-view ribbon diagram of the overall structure of S. aureus
GatCAB/glutamine complex at 2.3 Å resolution, depicted in
three different colors for each subunit: blue, green, and
magenta for GatA, GatB, and GatC, respectively. Glutamine in the
active site of GatA is drawn as yellow stick representations,
whereas the purple sphere is the magnesium ion found in the
active site of GatB. ADP from the cocrystal structure with
ADP-AlF[4]^- is shown together as pink sticks. This color code
is used throughout all the figures. (B) Top view of annularly
shaped GatC. (C) Amphipathic helices at the N terminus of GatC
form a helical bundle with the hydrophobic core of GatA
(hydrophobic residues are colored gray). (D) Detailed
interactions between the internal loop region of GatC and GatAB
complex. Conserved residues involved are labeled, with hydrogen
bonds indicated (  3.2 Å, dashed
black line). Polar interactions are prominent on the C-terminal
side, whereas the hydrophobic interactions are clustered on the
opposite side. (E) The C terminus of GatC tightens GatAB
complex, constructing an antiparallel ß sheet and a
hydrophobic platform.
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