1gq9
THE STRUCTURE OF CMP:2-KETO-3-DEOXY-MANNO-OCTONIC ACID SYNTHETASE COMPLEXED WITH CTP at 100K
Structural highlights
FunctionKPSU5_ECOLX Activates KDO (a required 8-carbon sugar) for incorporation into bacterial lipopolysaccharide in Gram-negative bacteria. 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 activation of the sugar 2-keto-3-deoxy-manno-octonic acid (Kdo) is catalyzed by CMP-Kdo synthetase (EC 2.7.7.38) and results in a monophosphate diester with CMP. The enzyme is a pharmaceutical target because CMP-Kdo is required for the biosynthesis of lipopolysaccharides that are vital for Gram-negative bacteria. We have established the structures of an enzyme complex with the educt CTP and of a complex with the product CMP-Kdo by X-ray diffraction analyses at 100 K, both at 2.6 A resolution. The N-terminal domains of the dimeric enzyme bind CTP in a peculiar nucleotide-binding fold with the beta- and gamma-phosphates located at the so-called "PP-loop", whereas the C-terminal domains participate in Kdo binding and in the dimer interface. The unstable nucleotide-sugar CMP-Kdo was produced in a crystal and stabilized by freezing to 100 K. Its formation is accompanied by an induced fit involving mainchain displacements in the 2 A range. The observed binding conformations together with the amino acid conservation pattern during evolution and the putative location of the required Mg(2+) ion suggest a reaction pathway. The enzyme is structurally homologous to the CMP-N-acetylneuraminic acid synthetases in all parts except for the dimer interface. Moreover, the chainfold and the substrate-binding positions resemble those of other enzymes processing nucleotide sugars. Catalytic mechanism of CMP:2-keto-3-deoxy-manno-octonic acid synthetase as derived from complexes with reaction educt and product.,Jelakovic S, Schulz GE Biochemistry. 2002 Jan 29;41(4):1174-81. PMID:11802716[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References | ||||||||||||||||||||
