1o8n

The active site of the molybdenum cofactor biosynthetic protein domain Cnx1G

spinqualitylabelsall models 1o8n, resolution 2.80Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1o8n is a 3 chain structure with sequence from Arabidopsis thaliana. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.8Å Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function CNX1_ARATH Catalyzes two steps in the biosynthesis of the molybdenum cofactor. In the first step, molybdopterin is adenylated. Subsequently, molybdate is inserted into adenylated molybdopterin and AMP is released. 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 PubMed The final step of molybdenum cofactor biosynthesis in plants is catalyzed by the two-domain protein Cnx1. The G domain of Cnx1 (Cnx1G) binds molybdopterin with high affinity and transfers molybdenum to molybdopterin. Here, we describe the functional and structural characterization of structure-based Cnx1G mutants. For molybdopterin binding residues Thr542 and Ser573 were found to be important because different mutations of those residues resulted in 7- to 26-fold higher k(D) values for molybdopterin binding. Furthermore, we showed that the terminal phosphate of molybdopterin is directly involved in protein-pterin interactions as dephosphorylated molybdopterin binds with one magnitude of order lower affinity to the wild-type protein. Molybdopterin binding was not affected in mutants defective in Ser476, Asp486, or Asp515. However, molybdenum insertion was completely abolished, indicating their important role for catalysis. Based on these results we propose the binding of molybdopterin to a large depression in the structure of Cnx1G formed by beta5, alpha5, beta6, and alpha6, whereas the negatively charged depression formed by the loop between beta3 and alpha4, the N-terminal end of alpha2, the 3(10) helix, and the region between beta6 and alpha6 is involved in catalysis. The active site of the molybdenum cofactor biosynthetic protein domain Cnx1G.,Kuper J, Winking J, Hecht HJ, Mendel RR, Schwarz G Arch Biochem Biophys. 2003 Mar 1;411(1):36-46. PMID:12590921 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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