1dak
DETHIOBIOTIN SYNTHETASE FROM ESCHERICHIA COLI, COMPLEX REACTION INTERMEDIATE ADP AND MIXED ANHYDRIDE
Structural highlights
FunctionBIOD1_ECOLI Catalyzes a mechanistically unusual reaction, the ATP-dependent insertion of CO2 between the N7 and N8 nitrogen atoms of 7,8-diaminopelargonic acid (DAPA) to form an ureido ring. Only CTP can partially replace ATP while diaminobiotin is only 37% as effective as 7,8-diaminopelargonic acid.[1] [2] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe ATP-dependent enzyme dethiobiotin synthetase from Escherichia coli catalyses the formation of dethiobiotin from CO2 and 7, 8-diaminopelargonic acid. The reaction is initiated by the formation of a carbamate and proceeds through a phosphorylated intermediate, a mixed carbamic phosphoric anhydride. Here, we report the crystal structures at 1.9- and 1.6-A resolution, respectively, of the enzyme-MgATP-diaminopelargonic acid and enzyme-MgADP-carbamic-phosphoric acid anhydride complexes, observed by using kinetic crystallography. Reaction initiation by addition of either NaHCO3 or diaminopelargonic acid to crystals already containing cosubstrates resulted in the accumulation of the phosphorylated intermediate at the active site. The phosphoryl transfer step shows inversion of the configuration at the phosphorus atom, consistent with an in-line attack by the carbamate oxygen onto the phosphorus atom of ATP. A key feature in the structure of the complex of the enzyme with the reaction intermediate is two magnesium ions, bridging the phosphates at the cleavage site. These magnesium ions compensate the negative charges at both phosphate groups after phosphoryl transfer and contribute to the stabilization of the reaction intermediate. Snapshot of a phosphorylated substrate intermediate by kinetic crystallography.,Kack H, Gibson KJ, Lindqvist Y, Schneider G Proc Natl Acad Sci U S A. 1998 May 12;95(10):5495-500. PMID:9576910[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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