7jx1

E. coli TSase complex with a bi-substrate reaction intermediate analog

spinqualitylabelsall models 7jx1, resolution 1.82Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.82Å Ligands: CXM, PO4, TMP, VLA, VLD Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Publication Abstract from PubMed Methylation of 2-deoxyuridine-5'-monophosphate (dUMP) at the C5 position by the obligate dimeric thymidylate synthase (TSase) in the sole de novo biosynthetic pathway to thymidine 5'-monophosphate (dTMP) proceeds by forming a covalent ternary complex with dUMP and cosubstrate 5,10-methylenetetrahydrofolate. The crystal structure of an analog of this intermediate gives important mechanistic insights but does not explain the half-of-the-sites activity of the enzyme. Recent experiments showed that the C5 proton and the catalytic Cys are eliminated in a concerted manner from the covalent ternary complex to produce a noncovalent bisubstrate intermediate. Here, we report the crystal structure of TSase with a close synthetic analog of this intermediate in which it has partially reacted with the enzyme but in only one protomer, consistent with the half-of-the-sites activity of this enzyme. Quantum mechanics/molecular mechanics simulations confirmed that the analog could undergo catalysis. The crystal structure shows a new water 2.9 A from the critical C5 of the dUMP moiety, which in conjunction with other residues in the network, may be the elusive general base that abstracts the C5 proton of dUMP during the reaction. Caught in Action: X-ray Structure of Thymidylate Synthase with Noncovalent Intermediate Analog.,Kholodar SA, Finer-Moore JS, Swiderek K, Arafet K, Moliner V, Stroud RM, Kohen A Biochemistry. 2021 Apr 8. doi: 10.1021/acs.biochem.1c00063. PMID:33829766 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Thymidylate synthase 3D structures

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