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Figure 1.
Figure 1. The DAHPS*Mn*PEP*Phe tetramer. (a) One of two
nearly identical +Phe tetramers in the asymmetric unit. Each of
the tight dimers forming the tetramer (AB and CD) consists of a
green and a purple subunit. The eight strands of the (b/a)[8]
barrel are blue in all subunits. Mn2+ (cyan) and PEP (gold) are
at the C-end of the barrel. Bound Phe (gold) is near the
inter-subunit b6a/b6b/b0^* sheets. The orange square outlines
the area represented in (b), which shows the superposition of
Leu16 and the Trp215-Gly216-His217 segments of four subunits of
-Phe (gray) and +Phe (same color as in (a)). The 222 symmetry of
the -Phe enzyme is reduced to 2-fold symmetry in the +Phe
enzyme. H-bonds formed in +Phe DAHPS are shown as light blue
dotted lines. All figures were drawn with RIBBONS.[15]
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