Thermostable OGG는 N-glycosylase와 AP-lyase 두 활성을 갖는 열안정성 8-옥소구아닌(8-oxoG) DNA 글리코실라제로 8-oxoG만 인식하고 절단하는 효소입니다.
- N-glycosylase: 이중 가닥 DNA에서 손상된 퓨린(8-oxoguanine)을 방출하여 AP site1)를 생성합니다.
- AP-lyase: 5′ phosphate와 3′-phospho-α, β-unsaturated aldehyde를 남기는 AP site의 3’을 절단하는 효소입니다.
1) DNA 손상으로 인해 퓨린(A or G) 이나 피리미딘(C or T) 염기가 없는 DNA의 위치
- Thermostable oxoguanine glycosylase
- Bifunctional DNA glycosylase with DNA N-glycosylase and AP lyase activities
- N-glycosylase activity releases 8-oxo-7,8-dihydroguanine (8-oxoG), generating an AP site. The AP-lyase activity cleaves 3′ to the AP site leaving a 5′ phosphate and a 3′-phospho-α, β-unsaturated aldehyde.
Figure 1: Unlike Fpg, Thermostable OGG specifically recognizes and cleaves only 8-oxoguanine and no other modified bases.
The ability to excise modified bases was queried by incubating Thermostable OGG (8 U) or Fpg (8 U) with fluorescently labeled dsDNA containing modified bases (either 8-oxoadenine, 5-hydroxycytosine, thymine glycol, 5-hydroxyuridine or 8-oxoguanine). Samples were analyzed by capillary electrophoresis and cleavage products are evidenced by the appearance of a cleaved product peak. Thermostable OGG only cleaves the 8-oxoguanine sample (top panel) while Fpg is active on other substrates including , 5-hydroxycytosine, thymine glycol and 5-hydroxyuridine (bottom panel).
Q&A
Thermostable OGG has activity in the following buffers:
| NEBuffer | r1.1 | r2.1 | r3.1 | rCutSmat |
| % Activity | 100 | 75 | 50 | 100 |
Thermopol Buffer=100% activity
The molecular weight of Thermostable OGG is 31,376 Da.
Yes, Thermostable OGG contains a C-terminal hexa-histidine tag.
Yes, Thermostable OGG will cleave ssDNA containing an 8-oxoguanine, however the activity on ssDNA is significantly reduced (~32-fold) as compared to activity on a dsDNA substrate.
