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The structure of L-fuculose-1-phosphate aldolase in a cubic crystal form has
been determined with and without the inhibitor phosphoglycolohydroxamate at 2.4
and 2.7 angstrom (1 angstrom = 0.1 nm) resolution, respectively. This inhibitor
mimics the enediolate transition state of the substrate moiety dihydroxyacetone
phosphate. The structures showed that dihydroxyacetone phosphate ligates the
zinc ion of this metal-dependent class II aldolase with its hydroxyl and keto
oxygen atoms, shifting Glu73 away from the zinc coordination sphere to a
non-polar environment. At this position Glu73 accepts a proton in the initial
reaction step, producing the enediolate which is then stabilized by the zinc
ion. The other substrate moiety L-lactaldehyde was modeled, because no binding
structure is yet available.
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