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Essawy MM, Campbell C. Enzymatic Processing of DNA-Protein Crosslinks. Genes (Basel) 2024; 15:85. [PMID: 38254974 PMCID: PMC10815813 DOI: 10.3390/genes15010085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Revised: 12/30/2023] [Accepted: 01/05/2024] [Indexed: 01/24/2024] Open
Abstract
DNA-protein crosslinks (DPCs) represent a unique and complex form of DNA damage formed by covalent attachment of proteins to DNA. DPCs are formed through a variety of mechanisms and can significantly impede essential cellular processes such as transcription and replication. For this reason, anti-cancer drugs that form DPCs have proven effective in cancer therapy. While cells rely on numerous different processes to remove DPCs, the molecular mechanisms responsible for orchestrating these processes remain obscure. Having this insight could potentially be harnessed therapeutically to improve clinical outcomes in the battle against cancer. In this review, we describe the ways cells enzymatically process DPCs. These processing events include direct reversal of the DPC via hydrolysis, nuclease digestion of the DNA backbone to delete the DPC and surrounding DNA, proteolytic processing of the crosslinked protein, as well as covalent modification of the DNA-crosslinked proteins with ubiquitin, SUMO, and Poly(ADP) Ribose (PAR).
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Affiliation(s)
| | - Colin Campbell
- Department of Pharmacology, University of Minnesota, Minneapolis, MN 55455, USA;
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Balint E, Unk I. For the Better or for the Worse? The Effect of Manganese on the Activity of Eukaryotic DNA Polymerases. Int J Mol Sci 2023; 25:363. [PMID: 38203535 PMCID: PMC10779026 DOI: 10.3390/ijms25010363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Revised: 12/22/2023] [Accepted: 12/24/2023] [Indexed: 01/12/2024] Open
Abstract
DNA polymerases constitute a versatile group of enzymes that not only perform the essential task of genome duplication but also participate in various genome maintenance pathways, such as base and nucleotide excision repair, non-homologous end-joining, homologous recombination, and translesion synthesis. Polymerases catalyze DNA synthesis via the stepwise addition of deoxynucleoside monophosphates to the 3' primer end in a partially double-stranded DNA. They require divalent metal cations coordinated by active site residues of the polymerase. Mg2+ is considered the likely physiological activator because of its high cellular concentration and ability to activate DNA polymerases universally. Mn2+ can also activate the known DNA polymerases, but in most cases, it causes a significant decrease in fidelity and/or processivity. Hence, Mn2+ has been considered mutagenic and irrelevant during normal cellular function. Intriguingly, a growing body of evidence indicates that Mn2+ can positively influence some DNA polymerases by conferring translesion synthesis activity or altering the substrate specificity. Here, we review the relevant literature focusing on the impact of Mn2+ on the biochemical activity of a selected set of polymerases, namely, Polβ, Polλ, and Polµ, of the X family, as well as Polι and Polη of the Y family of polymerases, where congruous data implicate the physiological relevance of Mn2+ in the cellular function of these enzymes.
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Affiliation(s)
| | - Ildiko Unk
- Institute of Genetics, HUN-REN Biological Research Centre Szeged, H-6726 Szeged, Hungary;
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Deshmukh PU, Lad SB, Sudarsan A, Sudhakar S, Aggarwal T, Mandal S, Bagale SS, Kondabagil K, Pradeepkumar PI. Human Translesion Synthesis Polymerases polκ and polη Perform Error-Free Replication across N2-dG Methyleugenol and Estragole DNA Adducts. Biochemistry 2023; 62:2391-2406. [PMID: 37486230 DOI: 10.1021/acs.biochem.2c00663] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/25/2023]
Abstract
The secondary metabolites of polypropanoids, methyleugenol (MEG), and estragole (EG), found in many herbs and spices, are commonly used as food flavoring agents and as ingredients in cosmetics. MEG and EG have been reported to cause hepatocarcinogenicity in rodents, human livers, and lung cells. The formation of N2-dG and N6-dA DNA adducts is primarily attributed to the carcinogenicity of these compounds. Therefore, these compounds have been classified as "possible human carcinogens" by the International Agency for Research on Cancer and "reasonably anticipated to be a human carcinogen" by the National Toxicology Program. Herein, we report the synthesis of the N2-MEG-dG and N2-EG-dG modified oligonucleotides to study the mutagenicity of these DNA adducts. Our studies show that N2-MEG-dG and N2-EG-dG could be bypassed by human translesion synthesis (TLS) polymerases hpolκ and hpolη in an error-free manner. The steady-state kinetics of dCTP incorporation by hpolκ across N2-MEG-dG and N2-EG-dG adducts show that the catalytic efficiencies (kcat/Km) were ∼2.5- and ∼4.4-fold higher, respectively, compared to the unmodified dG template. A full-length primer extension assay demonstrates that hpolκ exhibits better catalytic efficiency than hpolη. Molecular modeling and dynamics studies capturing pre-insertion, insertion, and post-insertion steps reveal the structural features associated with the efficient bypass of the N2-MEG-dG adduct by hpolκ and indicate the reorientation of the adduct in the active site allowing the successful insertion of the incoming nucleotide. Together, these results suggest that though hpolκ and hpolη perform error-free TLS across MEG and EG during DNA replication, the observed carcinogenicity of these adducts could be attributed to the involvement of other low fidelity polymerases.
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Affiliation(s)
- Priyanka U Deshmukh
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Shailesh B Lad
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Akhil Sudarsan
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Sruthi Sudhakar
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Tanvi Aggarwal
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Soumyadeep Mandal
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | | | - Kiran Kondabagil
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - P I Pradeepkumar
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
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Ghodke PP, Matse JH, Dawson S, Guengerich FP. Nucleophilic Thiol Proteins Bind Covalently to Abasic Sites in DNA. Chem Res Toxicol 2022; 35:1805-1808. [PMID: 35482010 DOI: 10.1021/acs.chemrestox.2c00068] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In the course of studies on the enhancement of 1,2-dibromoethane-induced DNA base pair mutations by O6-alkylguanine-DNA alkyltransferase (AGT, MGMT), we discovered the facile reaction of AGT with an abasic site in DNA, leading to covalent cross-linking. The binding of AGT differs from the mechanism reported for the protein HMCES; instead it appears to involve formation of a stable thioglycoside. Facile cross-linking was also observed with the protease papain, which like AGT has a low pKa cysteine, and the tripeptide glutathione.
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Affiliation(s)
- Pratibha P Ghodke
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-0146, United States
| | - Johannes H Matse
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-0146, United States
| | - Scott Dawson
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-0146, United States
| | - F Peter Guengerich
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-0146, United States
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