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Figure 6.
Figure 6. Comparison of apo [apo, this work, (purple)],
ethacrynic acid with no GSH [1GSF^5 (cyan)], S-ethacrynic acid
GSH [1GSE^5 (red)], S-benzyl-GSH [1GUH^4 (yellow)], and S-hexyl
GSH [GTX-GST-1.3, this work,(green)], in the region around GSH
showing helix  9
and helix 4
as cylinders. Only selected side-chains are shown for clarity.
The cofactors are drawn in ball-and-stick, while side-chains are
shown as solid frames. Short connecting chains are shown in
white. S-Hexyl GSH at the lower left can be seen to differ
little among the structures. Arg15 at the lower left is hydrogen
bonded to Glu104 on helix 4,
which lies vertically at the right. Tyr9 is directly beneath GSH
and Phe10 fans out underneath Phe220, which comes from helix
9,
running horizontal at the top of the figure. Phe10 in the apo
structure (purple) can be seen to occupy the place that Phe220
would occupy if the helix were localized in the apo structure.
Phe222 is also seen to systematically correlate with the
position of Phe10 (green/yellow/red/cyan: S-hexyl-GSH/S-benzyl
GSH/ethacrynic acid GSH/no GSH). Arg216 also seems to correlate
somewhat, although the order of the cyan and red side-chains are
interchanged relative to the Phe222 order. Leu 213 is packed
against Met 208 (also shown, just behind where the conjugates
lie, near where the two cylinders appear to touch). Met 208 is
also loosely in contact with Phe10 (there are no atoms directly
between the two side-chains, although they are 4.5 Å apart
and, in all except the present work, the thermal parameters for
the SD and CE are high compared to its remaining side-chain
atoms). Also shown on helix 4
are Leu107, Leu108, and Val111, residues that comprise part of
the H site.
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