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

Abstract : 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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https://hal.archives-ouvertes.fr/hal-01216639
Contributor : Isabelle Frapart <>
Submitted on : Friday, October 16, 2015 - 3:33:13 PM
Last modification on : Tuesday, May 14, 2019 - 3:54:01 PM

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R. Le Meur, F. 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, Portland Press, 2015, 471 (1), pp.13-23. ⟨10.1042/BJ20150387⟩. ⟨hal-01216639⟩

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