The RING-variant domain is a C4HC3 zinc-finger like motif found in a number of cellular and viral proteins.
Some of these proteins have been shown both in vivo and in vitro to have ubiquitin E3 ligase activity. The RING-variant domain is reminiscent of both the RING and the PHD domains and may represent an evolutionary intermediate. To describe this domain the term PHD/LAP domain has been used in the past. Extended description: The RING-variant (RINGv) domain contains a C4HC3 zinc-finger-like motif similar to the PHD domain, while some of the spacing between the Cys/His residues follow a pattern somewhat closer to that found in the RING domain. The RINGv domain, similar to the RING, PHD and LIM domains, is thought to bind two zinc ions co-ordinated by the highly conserved Cys and His residues. RING variant domain: C-x (2) -C-x(10-45)-C-x (1) -C-x (7) -H-x(2)-C-x(11-25)-C-x(2)-C As opposed to a PHD: C-x(1-2) -C-x (7-13)-C-x(2-4)-C-x(4-5)-H-x(2)-C-x(10-21)-C-x(2)-C Classical RING domain: C-x (2) -C-x (9-39)-C-x(1-3)-H-x(2-3)-C-x(2)-C-x(4-48) -C-x(2)-C