1XMS

E. coli RecA in complex with MnAMP-PNP

Summary for 1XMS

• Entry DOI: 10.2210/pdb1xms/pdb
• Descriptor: RecA protein, MANGANESE (II) ION, PHOSPHOAMINOPHOSPHONIC ACID-ADENYLATE ESTER, ... (4 entities in total)
• Functional Keywords: reca, homologous recombination, dna repair, atpase, dna-binding protein, dna binding protein
• Biological source: Escherichia coli
• Total number of polymer chains: 1
• Total formula weight: 38859.69

Authors

Bell, C.E.,Xing, X. (deposition date: 2004-10-04, release date: 2005-01-04, Last modification date: 2023-08-23)

Primary citation

Xing, X.,Bell, C.E.
Crystal Structures of Escherichia coli RecA in Complex with MgADP and MnAMP-PNP(,).
Biochemistry, 43:16142-16152, 2004

PubMed Abstract: RecA catalyzes the DNA pairing and strand-exchange steps of homologous recombination, an important mechanism for repair of double-stranded DNA breaks. The binding of RecA to DNA is modulated by adenosine nucleotides. ATP increases the affinity of RecA for DNA, while ADP decreases the affinity. Previously, the crystal structures of E. coli RecA and its complex with ADP have been determined to resolutions of 2.3 and 3.0 A, respectively, but the model for the RecA-ADP complex did not include magnesium ion or side chains. Here, we have determined the crystal structures of RecA in complex with MgADP and MnAMP-PNP, a nonhydrolyzable analogue of ATP, at resolutions of 1.9 and 2.1 A, respectively. Both crystals grow in the same conditions and have RecA in a right-handed helical form with a pitch of approximately 82 A. The crystal structures show the detailed interactions of RecA with the nucleotide cofactors, including the metal ion and the gamma phosphate of AMP-PNP. There are very few conformational differences between the structures of RecA bound to ADP and AMP-PNP, which differ from uncomplexed RecA only in a slight opening of the P-loop residues 66-73 upon nucleotide binding. To interpret the functional significance of the structure of the MnAMP-PNP complex, a coprotease assay was used to compare the ability of different nucleotides to promote the active, extended conformation of RecA. Whereas ATPgammaS and ADP-AlF(4) facilitate a robust coprotease activity, ADP and AMP-PNP do not activate RecA at all. We conclude that the crystal structure of the RecA-MnAMP-PNP complex represents a preisomerization state of the RecA protein that exists after ATP has bound but before the conformational transition to the active state.

PubMed: 15610008
DOI: 10.1021/bi048165y

Experimental method

X-RAY DIFFRACTION (2.1 Å)