CCCH zinc finger proteins are characterized by three cysteine residues and one histidine residue that coordinate the zinc ion and form, a CCCH-type zinc finger. In plant the most abundant type of CCCH finger is C-X8-C-X5-C-X3-H followed by C-X7-C-X5-C-X3-H other rare type of Zn-finger are also available in plant such as C-X7-C-X4-C-X3-H, C-X5-C-X4-C-X3-H, C-X7-CX6-C-X3-H etc. Although the majority of the CCCH motifs bind RNA, DNA binding CCCH-type zinc finger proteins have also been confirmed. Arabidopsis PEI encodes a protein containing a C3H zinc finger domain.
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