Recognition and processing of a new repertoire of DNA substrates by human 3-methyladenine DNA glycosylase (AAG)
The human 3-methyladenine DNA glycosylase (AAG) recognizes and excises a broad range of purines damaged by alkylation and oxidative damage, including 3-methyladenine, 7-methylguanine, hypoxanthine (Hx), and 1,N[superscript 6]-ethenoadenine (εA). The crystal structures of AAG bound to εA have provide...
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| Format: | Article |
| Language: | en_US |
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American Chemical Society
2011
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| Online Access: | http://hdl.handle.net/1721.1/66891 https://orcid.org/0000-0001-6159-0778 https://orcid.org/0000-0002-2196-5691 https://orcid.org/0000-0002-7112-1454 |
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| author | Lee, Chun-Yue I. Delaney, James C. Kartalou, Maria Lingaraju, Gondichatnahalli M. Maor-Shoshani, Ayelet Essigmann, John M. Samson, Leona D |
| author2 | Massachusetts Institute of Technology. Center for Environmental Health Sciences |
| author_facet | Massachusetts Institute of Technology. Center for Environmental Health Sciences Lee, Chun-Yue I. Delaney, James C. Kartalou, Maria Lingaraju, Gondichatnahalli M. Maor-Shoshani, Ayelet Essigmann, John M. Samson, Leona D |
| author_sort | Lee, Chun-Yue I. |
| collection | MIT |
| description | The human 3-methyladenine DNA glycosylase (AAG) recognizes and excises a broad range of purines damaged by alkylation and oxidative damage, including 3-methyladenine, 7-methylguanine, hypoxanthine (Hx), and 1,N[superscript 6]-ethenoadenine (εA). The crystal structures of AAG bound to εA have provided insights into the structural basis for substrate recognition, base excision, and exclusion of normal purines and pyrimidines from its substrate recognition pocket. In this study, we explore the substrate specificity of full-length and truncated Δ80AAG on a library of oligonucleotides containing structurally diverse base modifications. Substrate binding and base excision kinetics of AAG with 13 damaged oligonucleotides were examined. We found that AAG bound to a wide variety of purine and pyrimidine lesions but excised only a few of them. Single-turnover excision kinetics showed that in addition to the well-known εA and Hx substrates, 1-methylguanine (m1G) was also excised efficiently by AAG. Thus, along with εA and ethanoadenine (EA), m1G is another substrate that is shared between AAG and the direct repair protein AlkB. In addition, we found that both the full-length and truncated AAG excised 1,N[superscript 2]-ethenoguanine (1,N[superscript 2]-εG), albeit weakly, from duplex DNA. Uracil was excised from both single- and double-stranded DNA, but only by full-length AAG, indicating that the N-terminus of AAG may influence glycosylase activity for some substrates. Although AAG has been primarily shown to act on double-stranded DNA, AAG excised both εA and Hx from single-stranded DNA, suggesting the possible significance of repair of these frequent lesions in single-stranded DNA transiently generated during replication and transcription. |
| first_indexed | 2024-09-23T13:06:12Z |
| format | Article |
| id | mit-1721.1/66891 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T13:06:12Z |
| publishDate | 2011 |
| publisher | American Chemical Society |
| record_format | dspace |
| spelling | mit-1721.1/668912022-10-01T13:01:51Z Recognition and processing of a new repertoire of DNA substrates by human 3-methyladenine DNA glycosylase (AAG) Lee, Chun-Yue I. Delaney, James C. Kartalou, Maria Lingaraju, Gondichatnahalli M. Maor-Shoshani, Ayelet Essigmann, John M. Samson, Leona D Massachusetts Institute of Technology. Center for Environmental Health Sciences Massachusetts Institute of Technology. Department of Biological Engineering Massachusetts Institute of Technology. Department of Biology Massachusetts Institute of Technology. Department of Chemical Engineering Massachusetts Institute of Technology. Department of Chemistry Samson, Leona D. Lee, Chun-Yue I. Delaney, James C. Kartalou, Maria Lingaraju, Gondichatnahalli M. Maor-Shoshani, Ayelet Essigmann, John M. Samson, Leona D. The human 3-methyladenine DNA glycosylase (AAG) recognizes and excises a broad range of purines damaged by alkylation and oxidative damage, including 3-methyladenine, 7-methylguanine, hypoxanthine (Hx), and 1,N[superscript 6]-ethenoadenine (εA). The crystal structures of AAG bound to εA have provided insights into the structural basis for substrate recognition, base excision, and exclusion of normal purines and pyrimidines from its substrate recognition pocket. In this study, we explore the substrate specificity of full-length and truncated Δ80AAG on a library of oligonucleotides containing structurally diverse base modifications. Substrate binding and base excision kinetics of AAG with 13 damaged oligonucleotides were examined. We found that AAG bound to a wide variety of purine and pyrimidine lesions but excised only a few of them. Single-turnover excision kinetics showed that in addition to the well-known εA and Hx substrates, 1-methylguanine (m1G) was also excised efficiently by AAG. Thus, along with εA and ethanoadenine (EA), m1G is another substrate that is shared between AAG and the direct repair protein AlkB. In addition, we found that both the full-length and truncated AAG excised 1,N[superscript 2]-ethenoguanine (1,N[superscript 2]-εG), albeit weakly, from duplex DNA. Uracil was excised from both single- and double-stranded DNA, but only by full-length AAG, indicating that the N-terminus of AAG may influence glycosylase activity for some substrates. Although AAG has been primarily shown to act on double-stranded DNA, AAG excised both εA and Hx from single-stranded DNA, suggesting the possible significance of repair of these frequent lesions in single-stranded DNA transiently generated during replication and transcription. United States. National Institutes of Health (grant ES05355) United States. National Institutes of Health (grant CA75576) United States. National Institutes of Health (grant CA55042) United States. National Institutes of Health (grant ES02109) United States. National Institutes of Health (grant T32-ES007020) United States. National Institutes of Health (grant CA80024) United States. National Institutes of Health (grant CA26731) 2011-11-02T17:34:43Z 2011-11-02T17:34:43Z 2009-02 Article http://purl.org/eprint/type/JournalArticle 0006-2960 1520-4995 http://hdl.handle.net/1721.1/66891 Lee, Chun-Yue I. et al. “Recognition and Processing of a New Repertoire of DNA Substrates by Human 3-Methyladenine DNA Glycosylase (AAG).” Biochemistry 48 (2009): 1850-1861. Web. 2 Nov. 2011. © 2011 American Chemical Society https://orcid.org/0000-0001-6159-0778 https://orcid.org/0000-0002-2196-5691 https://orcid.org/0000-0002-7112-1454 en_US http://dx.doi.org/10.1021/bi8018898 Biochemistry Creative Commons Attribution-Noncommercial-Share Alike 3.0 http://creativecommons.org/licenses/by-nc-sa/3.0/ application/pdf American Chemical Society PubMed Central |
| spellingShingle | Lee, Chun-Yue I. Delaney, James C. Kartalou, Maria Lingaraju, Gondichatnahalli M. Maor-Shoshani, Ayelet Essigmann, John M. Samson, Leona D Recognition and processing of a new repertoire of DNA substrates by human 3-methyladenine DNA glycosylase (AAG) |
| title | Recognition and processing of a new repertoire of DNA substrates by human 3-methyladenine DNA glycosylase (AAG) |
| title_full | Recognition and processing of a new repertoire of DNA substrates by human 3-methyladenine DNA glycosylase (AAG) |
| title_fullStr | Recognition and processing of a new repertoire of DNA substrates by human 3-methyladenine DNA glycosylase (AAG) |
| title_full_unstemmed | Recognition and processing of a new repertoire of DNA substrates by human 3-methyladenine DNA glycosylase (AAG) |
| title_short | Recognition and processing of a new repertoire of DNA substrates by human 3-methyladenine DNA glycosylase (AAG) |
| title_sort | recognition and processing of a new repertoire of dna substrates by human 3 methyladenine dna glycosylase aag |
| url | http://hdl.handle.net/1721.1/66891 https://orcid.org/0000-0001-6159-0778 https://orcid.org/0000-0002-2196-5691 https://orcid.org/0000-0002-7112-1454 |
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