MICB 201 Lecture Notes - Lecture 10: Endonuclease, Methicillin, Wild Type
Document Summary
Chapter 4: antibiotics and antibiotic resistance in bacteria (continued) Spirochetes etc. : also studied less intensively in some. Tra proteins = proteins for conjugation: encoded by plasmid tra genes clustered in a tra operon, orit (= origin of transfer) another important nucleotide sequence. Pilus retraction pulls donor and recipient organisms together. Cell envelops of donor and recipient fuse to form conjugation bridge. Tru(cid:272)ture of (cid:272)o(cid:374)jugatio(cid:374) (cid:271)ridge is a (cid:862)(cid:271)la(cid:272)k (cid:271)o(cid:454)(cid:863) One strand of the plasmid is transferred to the recipient. The stra(cid:374)d (cid:862)lost(cid:863) fro(cid:373) the do(cid:374)or is repla(cid:272)ed (cid:271)(cid:455) (cid:272)o(cid:373)ple(cid:373)e(cid:374)tar(cid:455) dna s(cid:455)(cid:374)thesis i(cid:374)(cid:448)ol(cid:448)i(cid:374)g host dna pol and other replication proteins. Relaxase = a tra protein (enzyme) orit specific nucleotide sequence at which plasmid transfer starts. Relaxase reacts with the orit nucleotides: cleaves dna sugar-phosphate backbone of one strand in the middle of the orit sequence becoming covalently (cid:271)o(cid:374)ded to the 5" -p of the cleaved strand. The ssdna-relaxase complex is transported to the recipient.
