1qwg
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(New page: 200px<br /><applet load="1qwg" size="450" color="white" frame="true" align="right" spinBox="true" caption="1qwg, resolution 1.60Å" /> '''Crystal structure of...)
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Revision as of 22:56, 20 November 2007
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Crystal structure of Methanococcus jannaschii phosphosulfolactate synthase
Overview
Members of the enolase mechanistically diverse superfamily catalyze a wide, variety of chemical reactions that are related by a common mechanistic, feature, the abstraction of a proton adjacent to a carboxylate group., Recent investigations into the function and mechanism of the, phosphosulfolactate synthase encoded by the ComA gene in Methanococcus, jannaschii have suggested that ComA, which catalyzes the stereospecific, Michael addition of sulfite to phosphoenolpyruvate to form, phosphosulfolactate, may be a member of the enolase superfamily. The, ComA-catalyzed reaction, the first step in the coenzyme M biosynthetic, pathway, likely proceeds via a Mg2+ ion-stabilized enolate intermediate in, a manner similar to that observed for members of the enolase superfamily., ComA, however, has no significant sequence similarity to any known, enolase. Here we report the x-ray crystal structure of ComA to 1.7-A, resolution. The overall fold for ComA is an (alpha/beta)8 barrel that, assembles with two other ComA molecules to form a trimer in which three, active sites are created at the subunit interfaces. From the positions of, two ordered sulfate ions in the active site, a model for the binding of, phosphoenolpyruvate and sulfite is proposed. Despite its mechanistic, similarity to the enolase superfamily, the overall structure and active, site architecture of ComA are unlike any member of the enolase, superfamily, which suggests that ComA is not a member of the enolase, superfamily but instead acquired an enolase-type mechanism through, convergent evolution.
About this Structure
1QWG is a Single protein structure of sequence from Methanocaldococcus jannaschii with SO4 as ligand. Full crystallographic information is available from OCA.
Reference
The structural determination of phosphosulfolactate synthase from Methanococcus jannaschii at 1.7-A resolution: an enolase that is not an enolase., Wise EL, Graham DE, White RH, Rayment I, J Biol Chem. 2003 Nov 14;278(46):45858-63. Epub 2003 Sep 2. PMID:12952952
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