BIOL 2004 Lecture Notes - Lecture 8: Origin Recognition Complex, Dna Polymerase Iii Holoenzyme, Eukaryotic Dna Replication

• School: Virginia Tech
• Department: Biological Sciences
• Course: BIOL 2004
• Professor: Silke Hauf

Document Summary

Proteins binding the origin of replication: bacteria: initiator protein (dnaa in e. coli, eukaryotes: origin recognition complex (orc, provide the initial unwinding of dna, so that other factors can bind. Dna helicase and dna gyrase: dna helicase breaks the hydrogen bonds holding the two dna strands together, dna gyrase reduces the torsional strain that builds up ahead of the replication fork. In bacteria: dna polymerase iii is the main polymerase accomplishing replication, dna polymerase i removes and replaces primers, dna polymerase ii, iv, and v are involved in dna repair. Sliding clamp: encircles the dna strand, p(cid:396)o(cid:373)oti(cid:374)g high p(cid:396)o(cid:272)essi(cid:448)it(cid:455) (cid:894)dna pol(cid:455)(cid:373)e(cid:396)ase does (cid:374)ot (cid:858)fall off(cid:859)(cid:895) Dna ligase: dna ligase is needed to catalyze the formation of a phosphodiester bond without adding another nucleotide. Two special problems in eukaryotic dna replication (cid:862)li(cid:272)e(cid:374)si(cid:374)g(cid:863: makes su(cid:396)e that ea(cid:272)h o(cid:396)igi(cid:374) of (cid:396)epli(cid:272)atio(cid:374) o(cid:374)l(cid:455) (cid:858)fi(cid:396)es(cid:859) o(cid:374)(cid:272)e du(cid:396)i(cid:374)g o(cid:374)e (cid:272)ell (cid:272)(cid:455)(cid:272)le dna replicated once, and only once, replicating the chromosome ends.