2Z43

Structure of a twinned crystal of RadA

Summary for 2Z43

• Entry DOI: 10.2210/pdb2z43/pdb
• Related: 2dfl
• Descriptor: DNA repair and recombination protein radA (2 entities in total)
• Functional Keywords: archaea, filament, dna binding, recombination, molecular switch, reca, rad51, dmc1
• Biological source: Sulfolobus solfataricus
• Total number of polymer chains: 3
• Total formula weight: 107742.09

Authors

Chen, L.T.,Ko, T.P.,Wang, A.H.J.,Wang, T.F. (deposition date: 2007-06-12, release date: 2007-11-13, Last modification date: 2023-11-01)

Primary citation

Chen, L.T.,Ko, T.P.,Chang, Y.W.,Lin, K.A.,Wang, A.H.J.,Wang, T.F.
Structural and functional analyses of five conserved positively charged residues in the L1 and N-terminal DNA binding motifs of archaeal RADA protein
Plos One, 2:e858-e858, 2007

PubMed Abstract: RecA family proteins engage in an ATP-dependent DNA strand exchange reaction that includes a ssDNA nucleoprotein helical filament and a homologous dsDNA sequence. In spite of more than 20 years of efforts, the molecular mechanism of homology pairing and strand exchange is still not fully understood. Here we report a crystal structure of Sulfolobus solfataricus RadA overwound right-handed filament with three monomers per helical pitch. This structure reveals conformational details of the first ssDNA binding disordered loop (denoted L1 motif) and the dsDNA binding N-terminal domain (NTD). L1 and NTD together form an outwardly open palm structure on the outer surface of the helical filament. Inside this palm structure, five conserved basic amino acid residues (K27, K60, R117, R223 and R229) surround a 25 A pocket that is wide enough to accommodate anionic ssDNA, dsDNA or both. Biochemical analyses demonstrate that these five positively charged residues are essential for DNA binding and for RadA-catalyzed D-loop formation. We suggest that the overwound right-handed RadA filament represents a functional conformation in the homology search and pairing reaction. A new structural model is proposed for the homologous interactions between a RadA-ssDNA nucleoprotein filament and its dsDNA target.

PubMed: 17848989
DOI: 10.1371/journal.pone.0000858

Experimental method

X-RAY DIFFRACTION (1.93 Å)