Human RAD52 protein has extreme thermal stability

W. Ranatunga, D. Jackson, R. A. Flowers, Gloria E Borgstahl

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

The human RAD52 protein plays an important role in the earliest stages of chromosomal double-strand break repair via the homologous recombination pathway. Individual subunits of RAD52 associate into seven-membered rings. These rings can form higher order complexes. RAD52 binds to DNA breaks, and recent studies suggest that the higher order self-association of the rings promotes DNA end joining. Monomers of the RAD52(1-192) deletion mutant also associate into ring structures but do not form higher order complexes. The thermal stability of wild-type and mutant RAD52 was studied by differential scanning calorimetry. Three thermal transitions (labeled A, B, and C) were observed with melting temperatures of 38.8, 73.1, and 115.2 °C. The RAD52(1-192) mutant had only two thermal transitions at 47.6 and 100.9 °C (labeled B and C). Transitions were labeled such that transition C corresponds to complete unfolding of the protein. The effect of temperature and protein concentration on RAD52 self-association was analyzed by dynamic light scattering. From these data a four-state hypothetical model was developed to explain the thermal denaturation profile of wild-type RAD52. The three thermal transitions in this model were assigned as follows. Transition A was attributed to the disruption of higher order assemblies of RAD52 rings, transition B to the disruption of rings to individual subunits, and transition C to complete unfolding. The ring-shaped quaternary structure of RAD52 and the formation of higher ordered complexes of rings appear to contribute to the extreme stability of RAD52. Higher ordered complexes of rings are stable at physiological temperatures in vitro.

Original languageEnglish (US)
Pages (from-to)8557-8562
Number of pages6
JournalBiochemistry
Volume40
Issue number29
DOIs
StatePublished - Jul 24 2001

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Extreme Heat
Thermodynamic stability
Hot Temperature
Association reactions
Temperature
Denaturation
DNA
Dynamic light scattering
Recombinational DNA Repair
Protein Unfolding
DNA Breaks
Joining
Differential Scanning Calorimetry
Melting point
Differential scanning calorimetry
Proteins
Repair
Monomers
Freezing
human RAD52 protein

ASJC Scopus subject areas

  • Biochemistry

Cite this

Human RAD52 protein has extreme thermal stability. / Ranatunga, W.; Jackson, D.; Flowers, R. A.; Borgstahl, Gloria E.

In: Biochemistry, Vol. 40, No. 29, 24.07.2001, p. 8557-8562.

Research output: Contribution to journalArticle

Ranatunga, W, Jackson, D, Flowers, RA & Borgstahl, GE 2001, 'Human RAD52 protein has extreme thermal stability', Biochemistry, vol. 40, no. 29, pp. 8557-8562. https://doi.org/10.1021/bi0155089
Ranatunga, W. ; Jackson, D. ; Flowers, R. A. ; Borgstahl, Gloria E. / Human RAD52 protein has extreme thermal stability. In: Biochemistry. 2001 ; Vol. 40, No. 29. pp. 8557-8562.
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