| ²é¿´: 615 | »Ø¸´: 2 | ||
Davilkidгæ (³õÈëÎÄ̳)
|
[ÇóÖú]
Ò»¶Î»°ÔÚÏß·Ò룬¹ØÓÚDNAµÄ£¬Çó´óÅ£Ãǰïæ£¬Ê®Íò»ð¼±£¬ÔÚÏßµÈ
|
|
DNA oxidative damage is usually caused by highly reactive oxygen species (ROS), such as singlet oxygen, superoxide, hydrogen peroxide, and hydroxyl radical. Many chemical modifications in DNA damage (e.g.DNA cleavage, DNA-protein cross links, purine oxidation, etc.) stem from the reactions with ROS, in particular with hydroxyl radical (HO• . Hydroxyl radical is very rare in a living cell, but extremely reactive, scrambling electrons and hydrogen atoms from protein and metabolites in a diffusive manner, and even from stable biomolecules such as DNA and lipids. Both the heterocy lic base and sugar-phosphate backbone are vulnerable, in particular via electron abstraction on guanine base and hydrogen abstraction on ribose 5¡ä-C. If the nucleobase-repair systems are not able to immediately regenerate intact nucleobase, a mutation in genome would result from erroneous base pairing during replication or, consequently, DNA cleavage would occur consequently. It is also believed that metal ions such as iron and copper would enhance hydroxyl radical generation via Fenton chemistry.In short, DNA oxidative damage seems to begin with one-electron loss and formation of a radical cation ¡°hole¡±at the encounter position. The hole hops reversibly through electronic structure along the DNA helix, trapped at a guanine-rich place as a form of guanine radical cation (G•+). Hydrolysis of G•+ releases 8-hydroxy-2¡ä-deoxyguanosine (8-OHdG), upon consequential DNA repairing in vivo ×îÖ÷Òª·Òë×îºóÁ½¾äIn shortÒÔºóµÄ |
» ²ÂÄãϲ»¶
ÉúÎïѧ303Çóµ÷¼Á£¬Ò»Ö¾Ô¸»ªÖÐũ΢ÉúÎÁù¼¶Òѹý£¬ÓпÆÑÐÓÐÎÄÕ£¬µ³Ô±
ÒѾÓÐ4È˻ظ´
318Çóµ÷¼Á
ÒѾÓÐ5È˻ظ´
0703µ÷¼Á
ÒѾÓÐ11È˻ظ´
»¯Ñ§357·Ö£¬¿¼Ñе÷¼Á
ÒѾÓÐ10È˻ظ´
0854Çóµ÷¼Á
ÒѾÓÐ4È˻ظ´
272Çóµ÷¼Á
ÒѾÓÐ3È˻ظ´
µ÷¼ÁÇóÖú
ÒѾÓÐ13È˻ظ´
332Çóµ÷¼Á
ÒѾÓÐ8È˻ظ´
341Çóµ÷¼Á
ÒѾÓÐ3È˻ظ´
Ò»Ö¾Ô¸µç×ӿƼ¼´óѧ085600²ÄÁÏÓ뻯¹¤ 329·ÖÇóµ÷¼Á
ÒѾÓÐ10È˻ظ´
Davilkid
гæ (³õÈëÎÄ̳)
- Ó¦Öú: 0 (Ó×¶ùÔ°)
- ½ð±Ò: 580.1
- É¢½ð: 10
- Ìû×Ó: 31
- ÔÚÏß: 8.3Сʱ
- ³æºÅ: 3396418
- ×¢²á: 2014-09-03
- רҵ: ÃÚÄòϵͳ½áʯ
| ÕâÊǹØÓÚDNAÑõ»¯ËðÉ˵ģ¬Õâ¸öholeµ½µ×ÊÇʲôÒâ˼£¬»¹ÓÐÕâ¾äThe hole hops reversibly through electronic structure along the DNA helix |
2Â¥2017-03-05 22:35:49
Î÷Á¹ÌÚÉÙ
ͳæ (ÖøÃûдÊÖ)
- Ó¦Öú: 0 (Ó×¶ùÔ°)
- ½ð±Ò: 178.4
- É¢½ð: 1827
- ºì»¨: 10
- Ìû×Ó: 1085
- ÔÚÏß: 118.6Сʱ
- ³æºÅ: 3988600
- ×¢²á: 2015-07-24
- ÐÔ±ð: GG
- רҵ: »¯Ñ§ÉúÎïѧÓëÉúÎïÓлú»¯Ñ§

3Â¥2017-03-10 22:47:15














. Hydroxyl radical is very rare in a living cell, but extremely reactive, scrambling electrons and
»Ø¸´´ËÂ¥