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Genetic Studies of Human DNA Repair Proteins Using Yeast as a Model System
14:09

Genetic Studies of Human DNA Repair Proteins Using Yeast as a Model System

Published on: March 18, 2010

Comparative analysis of interaction of human and yeast DNA damage recognition complexes with damaged DNA in

Yuliya S Krasikova1, Nadejda I Rechkunova, Ekaterina A Maltseva

  • 1Institute of Chemical Biology and Fundamental Medicine, Novosibirsk 630090, Russia.

The Journal of Biological Chemistry
|February 28, 2013
PubMed

Insights

The XPC-RAD23B complex and yeast Rad4-Rad23 initiate DNA repair by binding damaged DNA with similar high affinity. Their precise positioning opposite DNA lesions highlights conserved mechanisms in eukaryotic DNA damage scanning.

Area of Science:

  • Molecular Biology
  • DNA Repair Mechanisms
  • Biochemistry

Background:

  • The XPC-RAD23B complex and its yeast ortholog Rad4-Rad23 are crucial for initiating global genome nucleotide excision repair.
  • Understanding their DNA binding and positioning is key to elucidating DNA damage recognition pathways.

Purpose of the Study:

  • To analyze the interaction of human XPC-RAD23B and yeast Rad4-Rad23 with damaged DNA.
  • To compare the DNA binding affinity and precise location of these homologous protein complexes on DNA lesions.

Main Methods:

  • Electrophoretic mobility shift assay (EMSA) to assess DNA binding.
  • Fluorescent depolarization measurements for quantitative binding affinity analysis.
  • Photocross-linking footprinting using photoreactive DNA analogs to determine protein location.

Main Results:

  • Human XPC-RAD23B and yeast Rad4-Rad23 exhibit similar high binding affinities (K(D) ~0.5-0.6 nM) to damaged DNA duplexes.
  • Both complexes bind preferentially to the DNA strand opposite the damaged nucleotide.
  • Photocross-linking data aligns with crystal structure analysis, confirming precise protein positioning.

Conclusions:

  • XPC-RAD23B and Rad4-Rad23 share conserved DNA binding and positioning mechanisms.
  • These findings underscore common structural principles in DNA damage-scanning proteins across eukaryotes.
  • The study provides insights into the initiation steps of nucleotide excision repair.

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