1O8O

The active site of the molybdenum cofactor biosynthetic protein domain Cnx1G

1O8O の概要

• エントリーDOI: 10.2210/pdb1o8o/pdb
• 関連するPDBエントリー: 1EAV 1O8N 1O8Q
• 分子名称: MOLYBDOPTERIN BIOSYNTHESIS CNX1 PROTEIN (2 entities in total)
• 機能のキーワード: molybdenum cofactor biosynthesis, cnx1g, mutants
• 由来する生物種: ARABIDOPSIS THALIANA (MOUSE-EAR CRESS)
• タンパク質・核酸の鎖数: 3
• 化学式量合計: 53188.51

構造登録者

Kuper, J.,Winking, J.,Hecht, H.J.,Schwarz, G.,Mendel, R.R. (登録日: 2002-11-28, 公開日: 2003-12-04, 最終更新日: 2023-12-13)

主引用文献

Kuper, J.,Winking, J.,Hecht, H.J.,Mendel, R.R.,Schwarz, G.
The Active Site of the Molybdenum Cofactor Biosynthetic Protein Domain Cnx1G
Arch.Biochem.Biophys., 411:36-, 2003

PubMed Abstract: 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.

PubMed: 12590921
DOI: 10.1016/S0003-9861(02)00714-2

実験手法

X-RAY DIFFRACTION (2.7 Å)