The nucleoid-associated protein HU enhances 8-oxoguanine base excision by the formamidopyrimidine-DNA glycosylase - Archive ouverte HAL
Article Dans Une Revue Biochemical Journal Année : 2015

The nucleoid-associated protein HU enhances 8-oxoguanine base excision by the formamidopyrimidine-DNA glycosylase

R. Le Meur
Françoise Culard
  • Fonction : Auteur
  • PersonId : 849396
V. Nadan
S. Goffinont
F. Coste
M. Guerin
K. Loth
C. Landon
B. Castaing

Résumé

The nucleoid-associated protein HU is involved in numerous DNA transactions and thus is essential in DNA maintenance and bacterial survival. The high affinity of HU for SSBs (single-strand breaks) has suggested its involvement in DNA protection, repair and recombination. SSB-containing DNA are major intermediates transiently generated by bifunctional DNA N-glycosylases that initiate the BER (base excision repair) pathway. Enzyme kinetics and DNA-binding experiments demonstrate that HU enhances the 8-oxoguanine-DNA glycosylase activity of Fpg (formamidopyrimidine-DNA glycosylase) by facilitating the release of the enzyme from its final DNA product (one nucleoside gap). We propose that the displacement of Fpg from its end-DNA product by HU is an active mechanism in which HU recognizes the product when it is still bound by Fpg. Through DNA binding, the two proteins interplay to form a transient ternary complex Fpg/DNA/HU which results in the release of Fpg and the molecular entrapment of SSBs by HU. These results support the involvement of HU in BER in vivo.
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Dates et versions

hal-01216639 , version 1 (16-10-2015)

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Citer

R. Le Meur, Françoise Culard, V. Nadan, S. Goffinont, F. Coste, et al.. The nucleoid-associated protein HU enhances 8-oxoguanine base excision by the formamidopyrimidine-DNA glycosylase. Biochemical Journal, 2015, 471 (1), pp.13-23. ⟨10.1042/BJ20150387⟩. ⟨hal-01216639⟩
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