Bacterial YedK represses plasmid DNA replication and transformation through its DNA single-strand binding activity

Hu, Wanglai; Wang, Yuli; Yang, Bingxu; Chen, Lin; Yu, Hao; Liu, Guang; Deng, Zixin; Ou, Hong‐Yu; He, Xinyi

doi:10.1016/j.micres.2021.126852

Cited by 2 publications

(1 citation statement)

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“…The mutL -lacking strain of T. thermophilus HB8 was transformed with these plasmids. The mutation rate of T. thermophilus HB8 cells was estimated by the Luria-Delbruck fluctuation assay as described previously ( 53 , 54 ). Single colonies of T. thermophilus HB8 on TR plates were inoculated into TR media and cultured at 70°C overnight.…”

Section: Methodsmentioning

confidence: 99%

Catalytic mechanism of the zinc-dependent MutL endonuclease reaction

et al. 2023

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DNA mismatch repair endonuclease MutL binds two zinc ions. However, the endonuclease activity of MutL is drastically enhanced by other divalent metals such as manganese, implying that MutL binds another catalytic metal at some site other than the zinc-binding sites. Here, we solved the crystal structure of the endonuclease domain ofAquifex aeolicusMutL in the manganese- or cadmium-bound form, revealing that these metals compete with zinc at the same sites. Mass spectrometry revealed that the MutL yielded 5′-phosphate and 3′-OH products, which is characteristic of the two-metal-ion mechanism. Crystallographic analyses also showed that the position and flexibility of a highly conserved Arg ofA. aeolicusMutL altered depending on the presence of zinc/manganese or the specific inhibitor cadmium. Site-directed mutagenesis revealed that the Arg was critical for the catalysis. We propose that zinc ion and its binding sites are physiologically of catalytic importance and that the two-metal-ion mechanism works in the reaction, where the Arg plays a catalytic role. Our results also provide a mechanistic insight into the inhibitory effect of a mutagen/carcinogen, cadmium, on MutL.

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Section: Methodsmentioning

confidence: 99%