A comparative analysis of Dmc1 and Rad51 nucleoprotein filaments.
The eukaryotic RecA homologs Rad51 and Dmc1 are essential for strand exchange between homologous chromosomes during meiosis. All members of the RecA family of recombinases polymerize on DNA to form helical nucleoprotein filaments, which is the active form of the protein. Here we compare the filament structures of the Rad51 and Dmc1 proteins from both human and budding yeast. Previous studies of Dmc1 filaments suggested that they might be structurally distinct from filaments of other members of the RecA family, including Rad51. The data presented here indicate that Rad51 and Dmc1 filaments are essentially identical with respect to several structural parameters, including persistence length, helical pitch, filament diameter, DNA base pairs per helical turn and helical handedness. These data, together with previous studies demonstrating similar in vitro recombinase activity for Dmc1 and Rad51, support the view that differences in the meiotic function of Rad51 and Dmc1 are more likely to result from the influence of distinct sets of accessory proteins than from intrinsic differences in filament structure.
Committee on Genetics, University of Chicago, Chicago, IL 60637, USA.
Sean D
SD
Sheridan
Xiong
X
Yu
Robyn
R
Roth
John E
JE
Heuser
Michael G
MG
Sehorn
Patrick
P
Sung
Edward H
EH
Egelman
Douglas K
DK
Bishop
D020029:Base Pairing; D018797:Cell Cycle Proteins / Q000737:chemistry / Q000648:ultrastructure*; D004247:DNA / Q000737:chemistry / Q000648:ultrastructure*; D004270:DNA, Circular / Q000648:ultrastructure; D004277:DNA, Single-Stranded / Q000648:ultrastructure; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000648:ultrastructure*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D046529:Microscopy, Electron, Transmission; D051135:Rad51 Recombinase / Q000737:chemistry / Q000648:ultrastructure*; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000648:ultrastructure*
D018797:Cell Cycle Proteins; C513033:DMC1 protein, S cerevisiae; D004270:DNA, Circular; D004277:DNA, Single-Stranded; D004268:DNA-Binding Proteins; D029701:Saccharomyces cerevisiae Proteins; D004247:DNA; C495151:RAD51 protein, S cerevisiae; C495153:RAD51 protein, human; D051135:Rad51 Recombinase; C074556:DMC1 protein, human