The Cys4 zinc finger of bacteriophage T7 primase in sequence-specific single-stranded DNA recognition

Takahiro Kusakabe, Anna V. Hine, Sven G. Hyberts, Charles C. Richardson

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51 Citations (Scopus)


Bacteriophage T7 DNA primase recognizes 5'-GTC-3' in single-stranded DNA. The primase contains a single Cys4 zinc-binding motif that is essential for recognition. Biochemical and mutagenic analyses suggest that the Cys4 motif contacts cytosine of 5'-GTC-3' and may also contribute to thymine recognition. Residues His33 and Asp31 are critical for these interactions. Biochemical analysis also reveals that T7 primase selectively binds CTP in the absence of DNA. We propose that bound CTP selects the remaining base G, of 5'-GTC-3', by base pairing. Our deduced mechanism for recognition of ssDNA by Cys4 motifs bears little resemblance to the recognition of trinucleotides of double-stranded DNA by Cys2His2 zinc fingers.

Original languageEnglish
Pages (from-to)4295-4300
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number8
Publication statusPublished - Apr 13 1999


All Science Journal Classification (ASJC) codes

  • General

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