Bibliographic Details
| Title: |
In vitro eradication of abasic site-mediated DNA-peptide/protein cross-links by Escherichia coli long-patch base excision repair. |
| Authors: |
Bryan, Cameron1, Xiaoying Wei1,2, Zhishuo Wang1, Kun Yang1 kun.yang@austin.utexas.edu |
| Source: |
Journal of Biological Chemistry. Jul2022, Vol. 298 Issue 7, p1-16. 16p. |
| Subject Terms: |
*DNA synthesis, *ESCHERICHIA coli, *DNA replication, *ENDONUCLEASES, *SCHIFF bases, *DNA damage |
| Abstract: |
Apurinic/apyrimidinic (AP or abasic) sites are among the most abundant DNA lesions. Numerous proteins within different organisms ranging from bacteria to human have been demonstrated to react with AP sites to form covalent Schiff base DNA-protein cross-links (DPCs). These DPCs are unstable due to their spontaneous hydrolysis, but the half-lives of these cross-links can be as long as several hours. Such longlived DPCs are extremely toxic due to their large sizes, which physically block DNA replication. Therefore, these adducts must be promptly eradicated to maintain genome integrity. Herein, we used in vitro reconstitution experiments with chemically synthesized, stable, and site-specific Schiff base APpeptide/protein cross-link analogs to demonstrate for the first time that this type of DPC can be repaired by Escherichia coli (E. coli) long-patch base excision repair. We demonstrated that the repair process requires a minimum of three enzymes and five consecutive steps, including: (1) 50-DNA strand incision of the DPC by endonuclease IV; (2 to 4) strand-displacement DNA synthesis, removal of the 50-deoxyribose phosphatepeptide/protein adduct-containing flap, and gap-filling DNA synthesis by DNA polymerase I; and (5) strand ligation by a ligase. We further demonstrated that endonuclease IV plays a major role in incising an AP-peptide cross-link within E. coli cell extracts. We also report that eradicating model AP-protein (11.2-36.1 kDa) DPCs is less efficient than that of an APpeptide10mer cross-link, supporting the emerging model that proteolysis is likely required for efficient DPC repair. [ABSTRACT FROM AUTHOR] |
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| Database: |
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