MICROM 410 Lecture Notes - Lecture 10: Dna Replication, Topoisomerase, Dna Supercoil
Document Summary
Bacteria use topoisomerases to condense their dna by supercoiling, then arrange that dna into a series of loops or domains, collectively called the nucleoid. Topoisomerases will bind to the dna backbone, cleave it, remain covalently attached to it and pass the dna molecules across each other. Supercoiling can be relaxed one loop at a time. 30 - 50 of the big dna loops in e. coli (nucleoid). Topoisomerases do have enzymatic functions; other proteins involved in coiling do not. Reduce torsional strain during replication = type of topoisomerase called gyrase. Topos are important anti-bacterial drug targets that normal human topoisomerase are not sensitive to. Dna is the cell"s memory, but rna makes info in dna accessible for functions by proteins. 20. 5% rna rrna 16. 4% trna 2. 5% mrna 1. 6% Replication ends on opposite side of chromosome from oric, at terminus, which has multiple copies of a terminator sequence (ter).
