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E1 initiator DNA binding specificity is unmasked by selective inhibition of non‐specific DNA binding
Author(s) -
Stenlund Arne
Publication year - 2003
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/cdg091
Subject(s) - biology , dna , dna binding protein , microbiology and biotechnology , dna clamp , dna binding site , genetics , biochemistry , gene , transcription factor , polymerase chain reaction , gene expression , promoter , reverse transcriptase
Initiator proteins are critical components of the DNA replication machinery and mark the site of initiation. This activity probably requires highly selective DNA binding; however, many initiators display modest specificity in vitro . We demonstrate that low specificity of the papillomavirus E1 initiator results from the presence of a non‐specific DNA‐binding activity, involved in melting, which masks the specificity intrinsic to the E1 DNA‐binding domain. The viral factor E2 restores specificity through a physical interaction with E1 that suppresses non‐specific binding. We propose that this arrangement, where one DNA‐binding activity tethers the initiator to ori while another alters DNA structure, is a characteristic of other viral and cellular initiator proteins. This arrangement would provide an explanation for the low selectivity observed for DNA binding by initiator proteins.