Site Specific Recombination

  • November 2019
  • PDF

This document was uploaded by user and they confirmed that they have the permission to share it. If you are author or own the copyright of this book, please report to us by using this DMCA report form. Report DMCA


Overview

Download & View Site Specific Recombination as PDF for free.

More details

  • Words: 224
  • Pages: 22
Lecture 28 Site Specific Recombination

Homework: What limits transposon mobility in humans?

λ

A site­specific recombination reaction.  The reaction is for a common class of  site­specific recombinases called  integrase­class recombinases (named  after bacteriiophage λ integrase, the first  one characterized). The reaction is  carried out within a tetramer of identical  subunits. Recombinase subunits bind to a  specific sequence, often called simply  the recombination site. ① One strand in  each DNA is cleaved at particular points  within the sequence. The nucleophile is  the OH group of an active­site Tyr  residue, and the product is a covalent  phosphotyrosine link between protein  and DNA. ② The cleaved strands join to  new partners, producing a Holliday  intermediate. Steps ③ and ④ complete  the reaction by a process similar to the  first two steps. The original sequence of  the recombination site is regenerated  after recombining the DNA flanking the  site. These steps occur within a complex  of multiple recombinase subunits that  sometimes includes other proteins not  shown here.

A site­specific recombination  reaction. A surface contour  model of a four­subunit  integrase­class recombinase  called the Cre recombinase,  bound to a Holliday structure  recombination intermediate  shown with light blue and dark  blue helix strands. The protein  has been rendered transparent  so that the bound DNA is  visible.

Phase variation

(site specific recombination)

Inverted Repeats

Inverted Repeats

(prokaryotic)

in the generation of antibody diversity

Related Documents

Site Specific Recombination
November 2019 3
Specific Knowledge
November 2019 15
Site
November 2019 39