Human DNA topoisomerase I: relaxation, roles, and damage control.

摘要: Human DNA topoisomerase I is an essential enzyme involved in resolving the torsional stress associated with replication, transcription, and chromatin condensation. The catalytic cycle of consists cleavage to form a covalent enzyme–DNA intermediate, relaxation, finally, religation phosphate backbone restore continuity DNA. Structure/function studies have elucidated flexible that relaxes through coordinated, controlled movements distinct domains. cellular roles are apparent throughout nucleus, but concentration processes acting on ribosomal results accumulation nucleolus. Although activity required these processes, can also deleterious effect cells. In event final step reaction prevented, I–DNA intermediate becomes toxic lesion must be repaired. complexities relaxation reaction, roles, pathways exist repair I-mediated damage highlight importance continued study this enzyme.