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Zinc fingers help read DNA sequences.. Zinc is an essential trace element for humans [1] [2] [3] and other animals, [4] for plants [5] and for microorganisms. [6] Zinc is required for the function of over 300 enzymes and 1000 transcription factors, [3] and is stored and transferred in metallothioneins.
A zinc finger is a small protein structural motif that is characterized by the coordination of one or more zinc ions (Zn 2+) which stabilizes the fold. The term zinc finger was originally coined to describe the finger-like appearance of a hypothesized structure from the African clawed frog ( Xenopus laevis ) transcription factor IIIA .
Zinc is a chemical element with the symbol Zn and atomic number 30. It is a slightly brittle metal at room temperature and has a shiny-greyish appearance when oxidation is removed. It is the first element in group 12 (IIB) of the periodic table .
For example, terpyridine, which is a tridentate ligand forms the complex [Zn(terpy)Cl 2]. Another example would involve a tripodal ligand such as Tris(2-aminoethyl)amine. Square pyramidal 5-coordinate Zinc is found in Tetra(4-pyridyl)porphinatomonopyridinezinc(II) [ 19 ] Solution studies of other 5-coordinate Zinc porphyrins have been reported.
The formal oxidation state of the oxygen atoms is − 1 ⁄ 2. In solutions at neutral pH, the superoxide ion disproportionates to molecular oxygen and hydrogen peroxide. 2 O − 2 + 2 H + → O 2 + H 2 O 2. In biology this type of reaction is called a dismutation reaction. It involves both oxidation and reduction of superoxide ions.
Naturally occurring zinc (30 Zn) is composed of the 5 stable isotopes 64 Zn, 66 Zn, 67 Zn, 68 Zn, and 70 Zn with 64 Zn being the most abundant (48.6% natural abundance).Twenty-eight radioisotopes have been characterised with the most stable being 65 Zn with a half-life of 244.26 days, and then 72 Zn with a half-life of 46.5 hours.
Examples include iron, essential to hemoglobin; and magnesium, essential to chlorophyll. Some elements are essential only to certain taxonomic groups of organisms, particularly the prokaryotes. For instance, the lanthanide series rare earths are essential for methanogens. As shown in the following table, there is strong evidence that 19 of the ...
Other groups use ZFNs with 4, 5 or 6 zinc fingers that target longer and presumably rarer sites and such ZFNs could theoretically yield less off-target activity. A comparison of a pair of 3-finger ZFNs and a pair of 4-finger ZFNs detected off-target cleavage in human cells at 31 loci for the 3-finger ZFNs and at 9 loci for the 4-finger ZFNs. [38]