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Orange carotenoid protein, N-terminal domain superfamily

SCOP classification
Root:   SCOP hierarchy in SUPERFAMILY [ 0] (11)
Class:   All alpha proteins [ 46456] (284)
Fold:   Orange carotenoid protein, N-terminal domain [ 81929]
Superfamily:   Orange carotenoid protein, N-terminal domain [ 81930]
Families:   Orange carotenoid protein, N-terminal domain [ 81931]

Superfamily statistics
Genomes (53) Uniprot 2018_03 genome PDB chains (SCOP 1.75)
Domains 131 632 1
Proteins 129 620 1

Functional annotation
General category Other
Detailed category Unknown function

Function annotation of SCOP domain superfamilies

InterPro annotation
Cross references IPR015233 SSF81930 Protein matches

Carotenoids such as beta-carotene, lycopene, lutein and beta-cryptoxanthine are produced in plants and certain bacteria, algae and fungi, where they function as accessory photosynthetic pigments and as scavengers of oxygen radicals for photoprotection. They are also essential dietary nutrients in animals. Orange carotenoid-binding proteins (OCP) were first identified in cyanobacterial species, where they occur associated with phycobilisome in the cellular thylakoid membrane. These proteins function in photoprotection, and are essential for inhibiting white and blue-green light non-photochemical quenching (NPQ) [PubMed17307930, PubMed16531492]. Carotenoids improve the photoprotectant activity by broadening OCP's absorption spectrum and facilitating the dissipation of absorbed energy. OCP acts as a homodimer, and binds one molecule of carotenoid (3'-hydroxyechinenone) and one chloride ion per subunit, where the carotenoid binding site is lined with a striking number of methionine residues. The carotenoid 3'-hydroxyechinenone is not found in higher plants. OCP has two domains: an N-terminal helical domain and a C-terminal domain that resembles a NTF2 (nuclear transport factor 2) domain. OCP can be proteolytically cleaved into a red form (RCP), which lacks 15 residues from the N-terminus and approximately 150 residues from the C-terminus [PubMed16034528].

This entry represents the N-terminal domain found predominantly in prokaryotic orange carotenoid proteins and related carotenoid-binding proteins. It adopts an alpha-helical structure consisting of two four-helix bundles [PubMed12517340].

InterPro database

PDBeMotif information about ligands, sequence and structure motifs
Cross references PDB entries
Ligand binding statistics
Nucleic-acid binding statistics
Occurrence of secondary structure elements
Occurrence of small 3D structural motifs

PDBeMotif resource

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Internal database links

Browse genome assignments for this superfamily. The SUPERFAMILY hidden Markov model library has been used to carry out SCOP domain assignments to all genomes at the superfamily level.

Alignments of sequences to 3 models in this superfamily are available by clicking on the 'Alignments' icon above. PDB sequences less than 40% identical are shown by default, but any other sequence(s) may be aligned. Select PDB sequences, genome sequences, or paste in or upload your own sequences.

Browse and view proteins in genomes which have different domain combinations including a Orange carotenoid protein, N-terminal domain domain.

Examine the distribution of domain superfamilies, or families, across the major taxonomic kingdoms or genomes within a kingdom. This gives an immediate impression of how superfamilies, or families, are restricted to certain kingdoms of life.

Explore domain occurrence network where nodes represent genomes and edges are domain architectures (shared between genomes) containing the superfamily of interest.

There are 3 hidden Markov models representing the Orange carotenoid protein, N-terminal domain superfamily. Information on how the models are built, and plots showing hydrophobicity, match emmission probabilities and insertion/deletion probabilities can be inspected.

Jump to [ Top of page · SCOP classification · InterPro annotation · PDBeMotif links · Functional annotation · Internal database links ]