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

被引:55
作者
Kusakabe, T
Hine, AV
Hyberts, SG
Richardson, CC
机构
[1] Harvard Univ, Sch Med, Dept Biol Chem & Mol Pharmacol, Boston, MA 02115 USA
[2] Aston Univ, Pharmaceut Sci Res Inst, Birmingham B4 7ET, W Midlands, England
关键词
D O I
10.1073/pnas.96.8.4295
中图分类号
O [数理科学和化学]; P [天文学、地球科学]; Q [生物科学]; N [自然科学总论];
学科分类号
07 ; 0710 ; 09 ;
摘要
Bacteriophage T7 DNA primase recognizes 5'-GTC-3' in single-stranded DNA. The primase contains a single Cys(4) zinc-binding motif that is essential for recognition. Biochemical and mutagenic analyses suggest that the Cys(4) motif contacts cytosine of 5'-GTC-3' and may also contribute to thymine recognition. Residues His(33) and Asp(31) 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 Cys(4) motifs bears little resemblance to the recognition of trinucleotides of double-stranded DNA by Cys(2)His(2) zinc fingers.
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页码:4295 / 4300
页数:6
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