Crystal structure of the fission yeast mitochondrial Holliday junction resolvase Ydc2.
Resolution of Holliday junctions into separate DNA duplexes requires enzymatic cleavage of an equivalent strand from each contributing duplex at or close to the point of strand exchange. Diverse Holliday junction-resolving enzymes have been identified in bacteria, bacteriophages, archaea and pox viruses, but the only eukaryotic examples identified so far are those from fungal mitochondria. We have now determined the crystal structure of Ydc2 (also known as SpCce1), a Holliday junction resolvase from the fission yeast Schizosaccharomyces pombe that is involved in the maintenance of mitochondrial DNA. This first structure of a eukaryotic Holliday junction resolvase confirms a distant evolutionary relationship to the bacterial RuvC family, but reveals structural features which are unique to the eukaryotic enzymes. Detailed analysis of the dimeric structure suggests mechanisms for junction isomerization and communication between the two active sites, and together with site-directed mutagenesis identifies residues involved in catalysis.
Ceschini
S
S
Section of Structural Biology, Institute of Cancer Research, Chester Beatty Laboratories, 237 Fulham Road, London SW3 6JB, UK.
Keeley
A
A
McAlister
M S
MS
Oram
M
M
Phelan
J
J
Pearl
L H
LH
Tsaneva
I R
IR
Barrett
T E
TE
D000595:Amino Acid Sequence; D001665:Binding Sites; D002384:Catalysis; D020134:Catalytic Domain; D003001:Cloning, Molecular; D018360:Crystallography, X-Ray; D019281:Dimerization; D004706:Endodeoxyribonucleases / Q000737:chemistry*; D019143:Evolution, Molecular; D007536:Isomerism; D008928:Mitochondria / Q000201:enzymology*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D016366:Open Reading Frames; D011485:Protein Binding; D011487:Protein Conformation; D017510:Protein Folding; D017433:Protein Structure, Secondary; D012568:Schizosaccharomyces / Q000201:enzymology*; D029702:Schizosaccharomyces pombe Proteins; D017386:Sequence Homology, Amino Acid
D029702:Schizosaccharomyces pombe Proteins; D004706:Endodeoxyribonucleases; C108766:cce1 protein, S pombe