Biochemical and genetic analysis of Lhr, a mysterious helicase/glycosylase conserved across species
Changes to DNA structure frequently inhibit essential processes such as DNA replication. Overcoming replication blockage or collapse requires replication-coupled DNA repair enzymes that catalyse removal of aberrant DNA structures and chemically modified bases. The Lhr family of helicases are found t...
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| Format: | Thesis (University of Nottingham only) |
| Language: | English |
| Published: |
2023
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| Online Access: | https://eprints.nottingham.ac.uk/72474/ |
| _version_ | 1848800743652327424 |
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| author | Buckley, Ryan J. |
| author_facet | Buckley, Ryan J. |
| author_sort | Buckley, Ryan J. |
| building | Nottingham Research Data Repository |
| collection | Online Access |
| description | Changes to DNA structure frequently inhibit essential processes such as DNA replication. Overcoming replication blockage or collapse requires replication-coupled DNA repair enzymes that catalyse removal of aberrant DNA structures and chemically modified bases. The Lhr family of helicases are found throughout archaea, including in the Heimdall- and Nano- archaeota, and are present in several bacterial clades. This family can be divided into ‘Lhr-core’ and ‘Lhr-extended’ protein variants with the latter containing an as yet uncharacterised extended C-terminal domain.
Through genetic analysis we identified an expression phenotype of archaeal Lhr identical to the replication-coupled DNA repair enzymes Hel308 and RecQ and implicated bacterial Lhr in a novel mutation repair pathway and in overcoming oxidative stress through interaction with a Rad51 paralogue.
In vitro analysis demonstrated archaeal Lhr preferential targeting of replication fork structures through ATP-independent binding causing melting/distortion of the branch point. This allowed loading for directional translocation and unwinding through the ‘parental’ DNA strands. Characterisation of bacterial Lhr-CTD revealed a newly identified d-uracil DNA glycosylase activity, building an emerging story about the contribution of Lhr and its associated proteins in prokaryotic DNA repair. Further context is afforded through phylogenetic analysis of RecA/Rad51 family proteins revealing the emergence of protein sub-families.
Here we present a substantial breakthrough in the study of Lhr proteins, implicating them for direct involvement in replication-coupled repair and a wider role in base excision repair. |
| first_indexed | 2025-11-14T20:56:25Z |
| format | Thesis (University of Nottingham only) |
| id | nottingham-72474 |
| institution | University of Nottingham Malaysia Campus |
| institution_category | Local University |
| language | English |
| last_indexed | 2025-11-14T20:56:25Z |
| publishDate | 2023 |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | nottingham-724742023-07-31T04:40:35Z https://eprints.nottingham.ac.uk/72474/ Biochemical and genetic analysis of Lhr, a mysterious helicase/glycosylase conserved across species Buckley, Ryan J. Changes to DNA structure frequently inhibit essential processes such as DNA replication. Overcoming replication blockage or collapse requires replication-coupled DNA repair enzymes that catalyse removal of aberrant DNA structures and chemically modified bases. The Lhr family of helicases are found throughout archaea, including in the Heimdall- and Nano- archaeota, and are present in several bacterial clades. This family can be divided into ‘Lhr-core’ and ‘Lhr-extended’ protein variants with the latter containing an as yet uncharacterised extended C-terminal domain. Through genetic analysis we identified an expression phenotype of archaeal Lhr identical to the replication-coupled DNA repair enzymes Hel308 and RecQ and implicated bacterial Lhr in a novel mutation repair pathway and in overcoming oxidative stress through interaction with a Rad51 paralogue. In vitro analysis demonstrated archaeal Lhr preferential targeting of replication fork structures through ATP-independent binding causing melting/distortion of the branch point. This allowed loading for directional translocation and unwinding through the ‘parental’ DNA strands. Characterisation of bacterial Lhr-CTD revealed a newly identified d-uracil DNA glycosylase activity, building an emerging story about the contribution of Lhr and its associated proteins in prokaryotic DNA repair. Further context is afforded through phylogenetic analysis of RecA/Rad51 family proteins revealing the emergence of protein sub-families. Here we present a substantial breakthrough in the study of Lhr proteins, implicating them for direct involvement in replication-coupled repair and a wider role in base excision repair. 2023-07-31 Thesis (University of Nottingham only) NonPeerReviewed application/pdf en cc_by https://eprints.nottingham.ac.uk/72474/1/Ryan%20Buckley_%20PhD%20Thesis_4342175.pdf Buckley, Ryan J. (2023) Biochemical and genetic analysis of Lhr, a mysterious helicase/glycosylase conserved across species. PhD thesis, University of Nottingham. Lhr DNA Helicase Glycosylase DNA repair DNA replication Genetics Biochemistry |
| spellingShingle | Lhr DNA Helicase Glycosylase DNA repair DNA replication Genetics Biochemistry Buckley, Ryan J. Biochemical and genetic analysis of Lhr, a mysterious helicase/glycosylase conserved across species |
| title | Biochemical and genetic analysis of Lhr, a mysterious helicase/glycosylase conserved across species |
| title_full | Biochemical and genetic analysis of Lhr, a mysterious helicase/glycosylase conserved across species |
| title_fullStr | Biochemical and genetic analysis of Lhr, a mysterious helicase/glycosylase conserved across species |
| title_full_unstemmed | Biochemical and genetic analysis of Lhr, a mysterious helicase/glycosylase conserved across species |
| title_short | Biochemical and genetic analysis of Lhr, a mysterious helicase/glycosylase conserved across species |
| title_sort | biochemical and genetic analysis of lhr, a mysterious helicase/glycosylase conserved across species |
| topic | Lhr DNA Helicase Glycosylase DNA repair DNA replication Genetics Biochemistry |
| url | https://eprints.nottingham.ac.uk/72474/ |