Modified RING finger, HC subclass (C3HC5-type), found in cell growth regulator with RING finger domain protein 1 (CGRRF1) and similar proteins
CGRRF1, also known as cell growth regulatory gene 19 protein (CGR19) or RING finger protein 197 (RNF197), functions as a novel biomarker to monitor endometrial sensitivity and response to insulin-sensitizing drugs, such as metformin, in the context of obesity. CGRRF1 contains a C-terminal modified C3HC5-type RING-HC finger, which is distinguished from typical C3HC4 RING-HC finger due to the existence of the additional cysteine residue in the middle portion of the RING finger domain.
Structure:2EA5; Homo sapiens CGRF1 binds two Zn2+ ions through its modified C3HC5-type RING-HC finger.
Comment:modified RING-HC finger (C3HC5-type), extra conserved cysteine is not involved in Zn binding
Comment:The C3HC5-type RING finger is distinguished from typical C3HC4 RING-HC finger and C3H2C3 RING-H2 finger due to the existence of the additional cysteine residue in the middle portion of the RING finger domain.
Comment:C3HC4-type RING-HC finger consensus motif: C-X2-C-X(9-39)-C-X(1-3)-H-X(2-3)-C-X2-C-X(4-48)-C-X2-C, where X is any amino acid and the number of X residues varies in different fingers
Comment:A RING finger typically binds two zinc atoms, with its Cys and/or His side chains in a unique "cross-brace" arrangement.