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Figure 4.
Fig. 4. a, interactions between cofactor SAH and CmaA1.
The detailed interactions are also listed in Table II. The
figure was prepared using LIGPLOT(54). b, interactions between 7
amino acid insertions (residues 153-159) of CmaA2 (orange) and
the N terminus compared with CmaA1 (blue). c, active site
architecture. SAH and DDDMAB are shown in green. Residues
136-140 are shown in orange. DDDMAB in CmaA2-SAH-DDDMAB
structure is superimposed with CmaA1-SAH-DDDMAB structure and is
shown in gray. The bicarbonate ion in the active site is shown
interacting with His-167, Cys-35, and Glu-140. The carbocation
intermediate of the reaction mechanism may be stabilized by
cation-  interactions
during catalysis, specifically by the aromatic ring of the
Tyr-33.
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