Catalytic domain structure and hypothesis for function of GIY-YIG intron endonuclease I-TevI.
I-TevI, a member of the GIY-YIG family of homing endonucleases, consists of an N-terminal catalytic domain and a C-terminal DNA-binding domain joined by a flexible linker. The GIY-YIG motif is in the N-terminal domain of I-TevI, which corresponds to a phylogenetically widespread catalytic cartridge that is often associated with mobile genetic elements. The crystal structure of the catalytic domain of I-TevI, the first of any GIY-YIG endonuclease, reveals a novel alpha/beta-fold with a central three-stranded antiparallel beta-sheet flanked by three helices. The most conserved and putative catalytic residues are located on a shallow, concave surface and include a metal coordination site. Similarities in the three-dimensional arrangement of the catalytically important residues and the cation-binding site with those of the His-Cys box endonuclease I-PpoI suggest the possibility of mechanistic relationships among these different families of homing endonucleases despite completely different folds.
Van Roey
Patrick
P
Wadsworth Center, New York State Department Health, Albany, New York 12201-0509, USA. vanroey@wadsworth.org
Meehan
Lisa
L
Kowalski
Joseph C
JC
Belfort
Marlene
M
Derbyshire
Victoria
V
D000595:Amino Acid Sequence; D020134:Catalytic Domain; D018360:Crystallography, X-Ray; D004706:Endodeoxyribonucleases / Q000737:chemistry* / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011487:Protein Conformation; D017510:Protein Folding; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism
D011994:Recombinant Proteins; D004706:Endodeoxyribonucleases; C065074:I-TEVI endonuclease