Ferguson ZNF Sandbox: Difference between revisions
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In some zinc finger structures, the His binding residues are replaced by two Cys residues. In other structures, there are six Cys residues that bind two zinc ions. In any case, the Zn2+ ions group together into small globular domains, which eliminates the need for larger, hydrophobic protein cores<ref>Voet, Donald; Voet, Judith G.; Pratt, Charlotte W. Fundamentals of Biochemistry: Life at the Molecular Level. 3rd Ed. Hoboken, NJ: Wiley, 2008</ref>. | In some zinc finger structures, the His binding residues are replaced by two Cys residues. In other structures, there are six Cys residues that bind two zinc ions. In any case, the Zn2+ ions group together into small globular domains, which eliminates the need for larger, hydrophobic protein cores<ref>Voet, Donald; Voet, Judith G.; Pratt, Charlotte W. Fundamentals of Biochemistry: Life at the Molecular Level. 3rd Ed. Hoboken, NJ: Wiley, 2008</ref>. | ||
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====DNA Binding==== | |||
In TFIIIA, there are nine consecutive zinc fingers. Individual zinc fingers can be positioned in both the major groove and across the minor groove of DNA. These results show how TFIIIA can recognize several separated DNA sequences by using fewer fingers than necessary for continuous winding in the major groove. The PDB entry to the left shows 6 zinc fingers bound to a stretch of DNA. With this interaction, TFIIIA helps control the transcription of the gene for ribosomal RNA. The string of zinc fingers curls along the DNA or RNA strands, binding in the grooves and extending amino acids inwards to read the bases. A single zinc finger does not bind very tightly and can only recognize 2 or 3 base pairs, but several can be strung together, causing the group to bind more tightly and allows it to read longer DNA sequences. This modular approach is so appealing that researchers are currently trying to design artificial zinc fingers with different specificities<ref>PMID:2503871</ref>. | |||
==Reference== | ==Reference== | ||
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