Ferguson ZNF Sandbox: Difference between revisions
From Proteopedia
Jump to navigationJump to search
No edit summary |
No edit summary |
||
| Line 6: | Line 6: | ||
The DNA-binding motif known as the zinc finger was first discovered by Klug in Transcription Factor IIIA in ''Xenopus laevis'', the African clawed toad. TFIIIA is a 344 residue protein that contains 9 repeated modules, which are about 30 residues each, that contain <scene name='Zinc_Fingers/Zinc_fingers_cys/3'>two invariant cysteines</scene> and <scene name='Zinc_Fingers/Zinc_fingers_his/4'>two invariant histidines</scene><ref>Voet, Donald; Voet, Judith G.; Pratt, Charlotte W. Fundamentals of Biochemistry: Life at the Molecular Level. 3rd Ed. Hoboken, NJ: Wiley, 2008</ref>. These are able to bind a zinc ion, allowing the protein to fold tightly around it. This protein stabilizer is found in thousands of different proteins in both plants and animals, but usually not in prokaryotic organisms. | The DNA-binding motif known as the zinc finger was first discovered by Klug in Transcription Factor IIIA in ''Xenopus laevis'', the African clawed toad. TFIIIA is a 344 residue protein that contains 9 repeated modules, which are about 30 residues each, that contain <scene name='Zinc_Fingers/Zinc_fingers_cys/3'>two invariant cysteines</scene> and <scene name='Zinc_Fingers/Zinc_fingers_his/4'>two invariant histidines</scene><ref>Voet, Donald; Voet, Judith G.; Pratt, Charlotte W. Fundamentals of Biochemistry: Life at the Molecular Level. 3rd Ed. Hoboken, NJ: Wiley, 2008</ref>. These are able to bind a zinc ion, allowing the protein to fold tightly around it. This protein stabilizer is found in thousands of different proteins in both plants and animals, but usually not in prokaryotic organisms. | ||
===Zinc Finger Structure=== | ===Zinc Finger Structure=== | ||
| Line 15: | Line 14: | ||
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>. | ||
{{STRUCTURE_1tf6| PDB=1tf6 | SCENE= }} | {{STRUCTURE_1tf6| PDB=1tf6 | SCENE= }} | ||
====DNA Binding==== | ====DNA Binding==== | ||
| Line 24: | Line 22: | ||
The DNA binding specificity is determined by sidechain-base interactions involving residues located at the end or on the surface of the helix <ref>Laity, John. "Zinc Finger Proteins: New Insights into Structural and Functional Diversity." Current Opinion in Structural Biology 11.1 (2001): 39-46.</ref>. Interactions between the phosphate backbone of DNA and linked zinc fingers may also play a role in the specificity. | The DNA binding specificity is determined by sidechain-base interactions involving residues located at the end or on the surface of the helix <ref>Laity, John. "Zinc Finger Proteins: New Insights into Structural and Functional Diversity." Current Opinion in Structural Biology 11.1 (2001): 39-46.</ref>. Interactions between the phosphate backbone of DNA and linked zinc fingers may also play a role in the specificity. | ||
====DNA Binding in mutant zinc finger domains==== | ====DNA Binding in mutant zinc finger domains==== | ||
