1EI1

DIMERIZATION OF E. COLI DNA GYRASE B PROVIDES A STRUCTURAL MECHANISM FOR ACTIVATING THE ATPASE CATALYTIC CENTER

1EI1 の概要

• エントリーDOI: 10.2210/pdb1ei1/pdb
• 分子名称: DNA GYRASE B, SULFATE ION, PHOSPHOAMINOPHOSPHONIC ACID-ADENYLATE ESTER, ... (5 entities in total)
• 機能のキーワード: atpase domain, dimer, isomerase
• 由来する生物種: Escherichia coli
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 87651.68

構造登録者

Brino, L.,Urzhumtsev, A.,Oudet, P.,Moras, D. (登録日: 2000-02-23, 公開日: 2000-03-31, 最終更新日: 2024-02-07)

主引用文献

Brino, L.,Urzhumtsev, A.,Mousli, M.,Bronner, C.,Mitschler, A.,Oudet, P.,Moras, D.
Dimerization of Escherichia coli DNA-gyrase B provides a structural mechanism for activating the ATPase catalytic center.
J.Biol.Chem., 275:9468-9475, 2000

PubMed Abstract: DNA-gyrase exhibits an unusual ATP-binding site that is formed as a result of gyrase B subunit dimerization, a structural transition that is also essential for DNA capture during the topoisomerization cycle. Previous structural studies on Escherichia coli DNA-gyrase B revealed that dimerization is the result of a polypeptidic exchange involving the N-terminal 14 amino acids. To provide experimental data that dimerization is critical for ATPase activity and enzyme turnover, we generated mutants with reduced dimerization by mutating the two most conserved residues of the GyrB N-terminal arm (Tyr-5 and Ile-10 residues). Our data demonstrate that the hydrophobic Ile-10 residue plays an important role in enzyme dimerization and the nucleotide-protein contact mediated by Tyr-5 side chain residue helps the dimerization process. Analysis of ATPase activities of mutant proteins provides evidence that dimerization enhances the ATP-hydrolysis turnover. The structure of the Y5S mutant of the N-terminal 43-kDa fragment of E. coli DNA GyrB subunit indicates that Tyr-5 residue provides a scaffold for the ATP-hydrolysis center. We describe a channel formed at the dimer interface that provides a structural mechanism to allow reactive water molecules to access the gamma-phosphate group of the bound ATP molecule. Together, these results demonstrate that dimerization strongly contributes to the folding and stability of the catalytic site for ATP hydrolysis. A role for the essential Mg(2+) ion for the orientation of the phosphate groups of the bound nucleotide inside the reactive pocket was also uncovered by superposition of the 5'-adenylyl beta-gamma-imidodiphosphate (ADPNP) wild-type structure to the salt-free ADPNP structure.

PubMed: 10734094
DOI: 10.1074/jbc.275.13.9468

実験手法

X-RAY DIFFRACTION (2.3 Å)