Conserved Protein Domain Family

cd00162: RING_Ubox 
Click on image for an interactive view with Cn3D
The superfamily of RING finger (Really Interesting New Gene) domain and U-box domain
RING finger is a specialized type of Zn-finger of 40 to 60 residues that binds two atoms of zinc. It is defined by the "cross-brace" motif that chelates zinc atoms by eight amino acid residues, typically Cys or His, arranged in a characteristic spacing. Canonical RING motifs have been categorized as two major subclasses, RING-HC (C3HC4-type) and RING-H2 (C3H2C3-type), according to their Cys/His content. There are also many variants of RING fingers. Some have different Cys/His pattern. Some lack a single Cys or His residues at typical Zn ligand positions. Especially, the fourth or eighth zinc ligand is prevalently exchanged for an Asp, which can indeed chelate Zn in a RING finger as well. C4C4-, C3HC3D-, C2H2C4-, and C3HC5-type RING fingers are closely related to RING-HC finger. In contrast, C4HC3- (RING-CH alias RINGv), C3H3C2-, C3H2C2D-, C3DHC3-, and C4HC2H-type RING fingers are close to RING-H2 finger. However, not all RING finger-containing proteins display regular RING finger features, and the RING finger family has turned out to be multifarious. The degenerated RING fingers from Siz/PIAS RING (SP-RING) family proteins and sporulation protein RMD5, are characterized by lacking the second, fifth, and sixth Zn2+ ion-coordinating residues. They bind only one Zn2+ ion. On the other hand, the RING fingers of the human APC11 and RBX1 proteins can bind a third Zn atom since they harbor four additional Zn ligands. U-box is a modified form of the RING finger domain that lacks metal chelating Cys and His. It resembles the cross-brace RING structure consisting of three beta-sheets and a single alpha-helix, which would be stabilized by salt bridges instead of chelated metal ions. U-box proteins are widely distributed among eukaryotic organisms and show a higher prevalence in plants than in other organisms. RING finger/U-box-containing proteins are a group of diverse proteins with a variety of cellular functions, including oncogenesis, development, viral replication, signal transduction, the cell cycle and apoptosis. Many of them are ubiquitin-protein ligases (E3s) that serves as a scaffold for binding to ubiquitin-conjugating enzymes (E2s, also referred to as ubiquitin carrier proteins or UBCs) in close proximity to substrate proteins, which enables efficient transfer of ubiquitin from E2 to the substrates.
PSSM-Id: 319361
Aligned: 6 rows
Threshold Bit Score: 40.9118
Threshold Setting Gi: 700588057
Created: 1-Nov-2000
Updated: 2-Oct-2020
Aligned Rows:
Conserved site includes 8 residues -Click on image for an interactive view with Cn3D
Feature 1:cross-brace motif
  • Comment:consensus of the canonical RING-HC/RING-H2 fingers: C-X2-C-X(9-39)-C-X(1-3)-C/H-X(2-3)-H-X2-C-X(4-48)-C-X2-C, X is any amino acid and the number of X residues varies in different fingers.

Sequence Alignment
Format: Row Display: Color Bits: Type Selection:
Feature 1     #  #                        # #  #  #                #    #
1FBV_A    335 CkICaendkd-------------vkiepCgHlmCtsCLTswqes-----egqgCPf--C 373 human
2MT5_A      9 CgICrmafngccpdckvpgddcplvwgqCsHcfHmhCILkwlhaq---qvqqhCPm--C 62  human
2YU4_A     10 CpITkeemkk------------pvknkvCgHtyEedAIVrmiesrqkrkkkayCPqigC 56  human
O00623    304 CpLCrktrvn------------dtvlatSgYvfCyrCVFhyvr------shqaCPi--T 342 human
Q6PCD5    287 CtICleqwtnag--------dhrlsalrCgHlfGyrCIStwlkg-----qvrkCPq--C 330 human
1WGM_A     25 DpIMstlmcd------------pvvlpsSrVtvDrsTIArhll------sdqtDPf--N 63  human

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