Regulation of E. coli Rep helicase activity by PriC

Nguyen, Binh; Shinn, Min Kyung; Weiland, Elizabeth; Lohman, Timothy M.

doi:10.1016/j.jmb.2021.167072

Cited by 20 publications

(22 citation statements)

References 84 publications

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“…This interaction also leads to enhanced processivity, which enables UvrD to unwind longer stretches of DNA when functioning with MutL ( 32 ). Similarly, the accessory factor PriC can activate the Rep monomer helicase and stimulate the Rep dimer helicase ( 76 ). By analogy, the nonhomologous end joining factor Mtb Ku has been reported to bind to the C-terminal region of UvrD1 ( 45 ), suggesting a role for UvrD1 in double-strand break repair.…”

Section: Discussionmentioning

confidence: 99%

Mycobacterium tuberculosis DNA repair helicase UvrD1 is activated by redox-dependent dimerization via a 2B domain cysteine

Chadda

Jensen

Tomko

et al. 2022

Proc. Natl. Acad. Sci. U.S.A.

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Mycobacterium tuberculosis (Mtb) causes tuberculosis and, during infection, is exposed to reactive oxygen species and reactive nitrogen intermediates from the host immune response that can cause DNA damage. UvrD-like proteins are involved in DNA repair and replication and belong to the SF1 family of DNA helicases that use ATP hydrolysis to catalyze DNA unwinding. In Mtb, there are two UvrD-like enzymes, where UvrD1 is most closely related to other family members. Previous studies have suggested that UvrD1 is exclusively monomeric; however, it is well known that Escherichia coli UvrD and other UvrD family members exhibit monomer–dimer equilibria and unwind as dimers in the absence of accessory factors. Here, we reconcile these incongruent studies by showing that Mtb UvrD1 exists in monomer, dimer, and higher-order oligomeric forms, where dimerization is regulated by redox potential. We identify a 2B domain cysteine, conserved in many Actinobacteria, that underlies this effect. We also show that UvrD1 DNA-unwinding activity correlates specifically with the dimer population and is thus titrated directly via increasing positive (i.e., oxidative) redox potential. Consistent with the regulatory role of the 2B domain and the dimerization-based activation of DNA unwinding in UvrD family helicases, these results suggest that UvrD1 is activated under oxidizing conditions when it may be needed to respond to DNA damage during infection.

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Section: Discussionmentioning

confidence: 99%

Mycobacterium tuberculosis DNA repair helicase UvrD1 is activated by redox-dependent dimerization via a 2B domain cysteine

Chadda

Jensen

Tomko

et al. 2022

Proc. Natl. Acad. Sci. U.S.A.

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“…These enzymes require activation in order to function as helicases and unwind DNA. This can occur by dimerization (44, 45), removal of an auto-inhibitory sub-domain (37) or through an interaction with an accessory protein, PriC for Rep (46), MutL for UvrD (47, 48), RepD for PcrA (49). Here we demonstrate a new mechanism for how the combined action of a directional ssDNA translocase and an SSB protein can acquire DNA unwinding activity.…”

Section: Discussionmentioning

confidence: 99%

“Helicase” Activity Promoted Through Dynamic Interactions Between a ssDNA Translocase and a Diffusing SSB Protein

Mersch

Sokoloski

Nguyen

et al. 2022

Preprint

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Replication protein A (RPA) is a eukaryotic single stranded (ss) DNA binding (SSB) protein that is essential for all aspects of genome maintenance. RPA binds ssDNA with high affinity but can also diffuse along ssDNA. By itself, RPA is capable of transiently disrupting short regions of duplex DNA by diffusing from a ssDNA that flanks the duplex DNA. Using single molecule total internal reflection fluorescence and optical trapping combined with fluorescence approaches we show that S. cerevisiae Pif1 can use its ATP-dependent 5 to 3 translocase activity to chemo-mechanically push a single human RPA (hRPA) directionally along ssDNA at rates comparable to those of Pif1 translocation alone. We further show that using its translocation activity Pif1 can push hRPA from a ssDNA loading site into a duplex DNA causing stable disruption of at least 9 bp of duplex DNA. These results highlight the dynamic nature of hRPA enabling it to be readily reorganized even when bound tightly to ssDNA and demonstrate a new mechanism by which directional DNA unwinding can be achieved through the combined action of a ssDNA translocase that pushes an SSB protein.

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“…The IDR C-terminal to the DciA domain in the V. cholerae homolog is required for its interaction with the DnaB helicase (35). IDRs in other replication proteins, including SSB and Rep, also play key roles in facilitating protein-protein interactions within the replisome (74)(75)(76)(77)(78)(79), indicating a common theme and function of these domains during bacterial DNA replication. However, if the IDR in the unstructured linker sequence is required for the interaction between DciA and the replicative helicase, this would imply that Group 4 DciA homologs, which only encode the DciA structural domain and no linker domains, employ other sequences or mechanisms to interact with DnaB.…”

Section: Discussionmentioning

confidence: 99%