Structural highlights
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.[1] [2] [3] [4]
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[5]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Llamas A, Mendel RR, Schwarz G. Synthesis of adenylated molybdopterin: an essential step for molybdenum insertion. J Biol Chem. 2004 Dec 31;279(53):55241-6. Epub 2004 Oct 25. PMID:15504727 doi:http://dx.doi.org/10.1074/jbc.M409862200
- ↑ Llamas A, Otte T, Multhaup G, Mendel RR, Schwarz G. The Mechanism of nucleotide-assisted molybdenum insertion into molybdopterin. A novel route toward metal cofactor assembly. J Biol Chem. 2006 Jul 7;281(27):18343-50. Epub 2006 Apr 24. PMID:16636046 doi:http://dx.doi.org/10.1074/jbc.M601415200
- ↑ Kuper J, Winking J, Hecht HJ, Mendel RR, Schwarz G. The active site of the molybdenum cofactor biosynthetic protein domain Cnx1G. Arch Biochem Biophys. 2003 Mar 1;411(1):36-46. PMID:12590921
- ↑ Kuper J, Llamas A, Hecht HJ, Mendel RR, Schwarz G. Structure of the molybdopterin-bound Cnx1G domain links molybdenum and copper metabolism. Nature. 2004 Aug 12;430(7001):803-6. PMID:15306815 doi:10.1038/nature02681
- ↑ Kuper J, Winking J, Hecht HJ, Mendel RR, Schwarz G. The active site of the molybdenum cofactor biosynthetic protein domain Cnx1G. Arch Biochem Biophys. 2003 Mar 1;411(1):36-46. PMID:12590921
