Oligomeric structure diversity within the GIY-YIG nuclease family.
The GIY-YIG nuclease domain has been identified in homing endonucleases, DNA repair and recombination enzymes, and restriction endonucleases. The Type II restriction enzyme Eco29kI belongs to the GIY-YIG nuclease superfamily and, like most of other family members, including the homing endonuclease I-TevI, is a monomer. It recognizes the palindromic sequence 5'-CCGC/GG-3' ("/" marks the cleavage position) and cuts it to generate 3'-staggered ends. The Eco29kI monomer, which contains a single active site, either has to nick sequentially individual DNA strands or has to form dimers or even higher-order oligomers upon DNA binding to make a double-strand break at its target site. Here, we provide experimental evidence that Eco29kI monomers dimerize on a single cognate DNA molecule forming the catalytically active complex. The mechanism described here for Eco29kI differs from that of Cfr42I isoschisomer, which also belongs to the GIY-YIG family but is functional as a tetramer. This novel mechanism may have implications for the function of homing endonucleases and other enzymes of the GIY-YIG family.
Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, Pushchino, Moscow Region, Russia.
Elena M
EM
Ibryashkina
Giedrius
G
Sasnauskas
Alexander S
AS
Solonin
Marina V
MV
Zakharova
Virginijus
V
Siksnys
D001483:Base Sequence; D001704:Biopolymers / Q000737:chemistry* / Q000378:metabolism; D004247:DNA / Q000378:metabolism; D015252:Deoxyribonucleases, Type II Site-Specific / Q000737:chemistry* / Q000378:metabolism; D019281:Dimerization; D006868:Hydrolysis; D007700:Kinetics; D011487:Protein Conformation
D001704:Biopolymers; D004247:DNA; C035337:CCGCGG-specific type II deoxyribonucleases; D015252:Deoxyribonucleases, Type II Site-Specific