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Protein Interactions in the T7 DNA Replisome Facilitate DNA Damage Bypass
Author(s) -
Zou Zhenyu,
Chen Ze,
Xue Qizhen,
Xu Ying,
Xiong Jingyuan,
Yang Ping,
Le Shuai,
Zhang Huidong
Publication year - 2018
Publication title -
chembiochem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.05
H-Index - 126
eISSN - 1439-7633
pISSN - 1439-4227
DOI - 10.1002/cbic.201800203
Subject(s) - replisome , primase , dna polymerase , dna clamp , dna polymerase ii , biology , dna replication , replication protein a , helicase , dna , dna damage , control of chromosome duplication , microbiology and biotechnology , circular bacterial chromosome , biochemistry , dna binding protein , gene , polymerase chain reaction , reverse transcriptase , rna , transcription factor
Abstract The DNA replisome inevitably encounters DNA damage during DNA replication. The T7 DNA replisome contains a DNA polymerase (gp5), the processivity factor thioredoxin (trx), a helicase‐primase (gp4), and a ssDNA‐binding protein (gp2.5). T7 protein interactions mediate this DNA replication. However, whether the protein interactions could promote DNA damage bypass is still little addressed. In this study, we investigated strand‐displacement DNA synthesis past 8‐oxoG or O 6 ‐MeG lesions at the synthetic DNA fork by the T7 DNA replisome. DNA damage does not obviously affect the binding affinities between helicase, polymerase, and DNA fork. Relative to unmodified G, both 8‐oxoG and O 6 ‐MeG—as well as GC‐rich template sequence clusters—inhibit strand‐displacement DNA synthesis and produce partial extension products. Relative to the gp4 ΔC‐tail, gp4 promotes DNA damage bypass. The presence of gp2.5 also promotes it. Thus, the interactions of polymerase with helicase and ssDNA‐binding protein facilitate DNA damage bypass. Accessory proteins in other complicated DNA replisomes also facilitate bypassing DNA damage in similar manner. This work provides new mechanistic information relating to DNA damage bypass by the DNA replisome.