P74102 · OCP_SYNY3
- ProteinOrange carotenoid-binding protein
- StatusUniProtKB reviewed (Swiss-Prot)
- Amino acids317 (go to sequence)
- Protein existenceEvidence at protein level
- Annotation score5/5
Function
function
Acts as a blue-light photoreceptor and photo-protectant. Essential for inhibiting damaged induced by excess blue-green light via a process known as non-photochemical quenching (NPQ) (PubMed:16531492, PubMed:18687902, PubMed:20368334).
In the dark or dim light the stable inactive form (OCP-O) is orange, upon illumination with blue-green light it converts to a metastable active red form (OCP-R), inducing energy dissipation, quenching cellular fluorescence via NPQ (PubMed:18687902, PubMed:20368334).
One OCP-R molecule is sufficient to quench 1 phycobilisome (PubMed:21764991).
More OCP-R accumulates under high-light and low temperature; in the dark OCP-R spontaneously reverts to OCP-O (PubMed:18687902).
Reversion of OCP-O is accelerated by FRP (PubMed:20534537, PubMed:23716688).
A kinetic study suggests conversion of OCP-O to OCP-R is limited by cis-trans proline isomerization of either Gln224-Pro225 or Pro225-Pro226 (PubMed:21907180).
In the dark or dim light the stable inactive form (OCP-O) is orange, upon illumination with blue-green light it converts to a metastable active red form (OCP-R), inducing energy dissipation, quenching cellular fluorescence via NPQ (PubMed:18687902, PubMed:20368334).
One OCP-R molecule is sufficient to quench 1 phycobilisome (PubMed:21764991).
More OCP-R accumulates under high-light and low temperature; in the dark OCP-R spontaneously reverts to OCP-O (PubMed:18687902).
Reversion of OCP-O is accelerated by FRP (PubMed:20534537, PubMed:23716688).
A kinetic study suggests conversion of OCP-O to OCP-R is limited by cis-trans proline isomerization of either Gln224-Pro225 or Pro225-Pro226 (PubMed:21907180).
Cofactor
Note: Binds 1 carotenoid molecule per subunit (3'-hydroxyechinenone is the physiological carotenoid, echinenone (70%), 3'-hydroxyechinenone (16%) or zeaxanthin (14%) were all detected in overexpressed, crystallized protein), makes contacts with both domains of the whole protein (PubMed:20368334).
Upon RCP generation the carotenoid translocates 12 Angstroms into the N-terminal domain, altering its binding and photochemical properties (PubMed:26113721).
Upon RCP generation the carotenoid translocates 12 Angstroms into the N-terminal domain, altering its binding and photochemical properties (PubMed:26113721).
Absorption
A double maxima at 467 and 495 nm is seen for the orange (inactive) form, the red (active) form has a single maximum at ~505 nm.
Features
Showing features for binding site.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Binding site | 34-38 | echinenone (UniProtKB | ChEBI); only in form RCP | ||||
Sequence: EDQLA | ||||||
Binding site | 37-44 | echinenone (UniProtKB | ChEBI); in forms OCP and RCP | ||||
Sequence: LALIWFAY | ||||||
Binding site | 80-83 | echinenone (UniProtKB | ChEBI); only in form RCP | ||||
Sequence: TQAM | ||||||
Binding site | 107-117 | echinenone (UniProtKB | ChEBI); in forms OCP and RCP | ||||
Sequence: LGFWYRLGELM | ||||||
Binding site | 125-129 | echinenone (UniProtKB | ChEBI); only in form RCP | ||||
Sequence: IPAGY | ||||||
Binding site | 151-161 | echinenone (UniProtKB | ChEBI); residues alter contact in forms OCP and RCP | ||||
Sequence: ITVLRNAVVDM | ||||||
Binding site | 201 | echinenone (UniProtKB | ChEBI); only in form OCP | ||||
Sequence: Y | ||||||
Binding site | 245-250 | echinenone (UniProtKB | ChEBI); only in form OCP | ||||
Sequence: CQNLKL | ||||||
Binding site | 273-284 | echinenone (UniProtKB | ChEBI); only in form OCP | ||||
Sequence: VQTPWFGGNVGM | ||||||
Binding site | 288 | echinenone (UniProtKB | ChEBI); only in form OCP | ||||
Sequence: W |
GO annotations
Aspect | Term | |
---|---|---|
Cellular Component | phycobilisome | |
Cellular Component | plasma membrane-derived thylakoid membrane | |
Molecular Function | chloride ion binding | |
Molecular Function | photoreceptor activity | |
Biological Process | light absorption |
Keywords
- Molecular function
- Biological process
- Ligand
Names & Taxonomy
Protein names
- Recommended nameOrange carotenoid-binding protein
- Short namesOCP
- Cleaved into 1 chains
Gene names
Organism names
- Strain
- Taxonomic lineageBacteria > Cyanobacteriota > Cyanophyceae > Synechococcales > Merismopediaceae > Synechocystis
Accessions
- Primary accessionP74102
Proteomes
Subcellular Location
UniProt Annotation
GO Annotation
Cellular thylakoid membrane ; Peripheral membrane protein
Note: Associated with the phycobilisome on the cytoplasmic side of the thylakoid membrane (PubMed:16531492).
Keywords
- Cellular component
Phenotypes & Variants
Disruption phenotype
Loss of NPQ induced by strong white or blue-green light, cells are more sensitive to high light.
Features
Showing features for mutagenesis.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Mutagenesis | 34 | Alters carotenoid specificity, <40% quenching, decreases stability of OCP-R, accelerates OCP-R to OCP-O reversion. | ||||
Sequence: E → A | ||||||
Mutagenesis | 44 | Acts like wild-type. | ||||
Sequence: Y → F | ||||||
Mutagenesis | 44 | Cannot convert to red form (OCP-R), no NPQ. Does not bind to phycobilisomes. | ||||
Sequence: Y → S | ||||||
Mutagenesis | 84 | <40% quenching, decreases stability of OCP-R, accelerates OCP-R to OCP-O reversion. | ||||
Sequence: C → A | ||||||
Mutagenesis | 110 | Acts like wild-type. | ||||
Sequence: W → F | ||||||
Mutagenesis | 110 | Incomplete conversion to red form (OCP-R), no NPQ. | ||||
Sequence: W → S | ||||||
Mutagenesis | 126 | <40% quenching, decreases stability of OCP-R, accelerates OCP-R to OCP-O reversion. | ||||
Sequence: P → V | ||||||
Mutagenesis | 126-129 | Cannot convert to red form (OCP-R). | ||||
Sequence: PAGY → VAGF | ||||||
Mutagenesis | 129 | <40% quenching, decreases stability of OCP-R, accelerates OCP-R to OCP-O reversion. | ||||
Sequence: Y → F | ||||||
Mutagenesis | 155 | Able to convert to red form (OCP-R), no NPQ. | ||||
Sequence: R → L |
PTM/Processing
Features
Showing features for initiator methionine, chain.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Initiator methionine | 1 | Removed | ||||
Sequence: M | ||||||
Chain | PRO_0000282352 | 2-317 | Orange carotenoid-binding protein | |||
Sequence: PFTIDSARGIFPNTLAADVVPATIARFSQLNAEDQLALIWFAYLEMGKTLTIAAPGAASMQLAENALKEIQAMGPLQQTQAMCDLANRADTPLCRTYASWSPNIKLGFWYRLGELMEQGFVAPIPAGYQLSANANAVLATIQGLESGQQITVLRNAVVDMGFTAGKDGKRIAEPVVPPQDTASRTKVSIEGVTNATVLNYMDNLNANDFDTLIELFTSDGALQPPFQRPIVGKENVLRFFREECQNLKLIPERGVTEPAEDGFTQIKVTGKVQTPWFGGNVGMNIAWRFLLNPEGKIFFVAIDLLASPKELLNFAR | ||||||
Chain | PRO_0000282353 | 16-? | Red carotenoid-binding protein | |||
Sequence: MPFTIDSARGIFPNT |
Post-translational modification
Proteolytically cleaved into a red 16.7 kDa form named red carotenoid-binding protein (RCP) which lacks 15 residues from the N-terminus and approximately 150 residues from the C-terminus (PubMed:9398074).
Proteomic databases
Expression
Induction
Transcribed from its own promoter, it may also be cotranscribed with downstream frp.
Interaction
Subunit
Monomer (PubMed:20368334).
Interacts with the APC core of the phycobilisome (PB), probably at a ratio of 1:1 in a light-independent manner; possibly only OCP-R binds to PBs. Interacts with FRP (PubMed:20534537, PubMed:23716688).
Detachment from PBs is accelerated by FPR (PubMed:21764991).
Interacts with the APC core of the phycobilisome (PB), probably at a ratio of 1:1 in a light-independent manner; possibly only OCP-R binds to PBs. Interacts with FRP (PubMed:20534537, PubMed:23716688).
Detachment from PBs is accelerated by FPR (PubMed:21764991).
Binary interactions
Type | Entry 1 | Entry 2 | Number of experiments | Intact | |
---|---|---|---|---|---|
BINARY | P74102 | frp P74103 | 2 | EBI-1618104, EBI-1618115 |
Protein-protein interaction databases
Structure
Family & Domains
Features
Showing features for domain.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Domain | 18-169 | OCP N-terminal | ||||
Sequence: ADVVPATIARFSQLNAEDQLALIWFAYLEMGKTLTIAAPGAASMQLAENALKEIQAMGPLQQTQAMCDLANRADTPLCRTYASWSPNIKLGFWYRLGELMEQGFVAPIPAGYQLSANANAVLATIQGLESGQQITVLRNAVVDMGFTAGKDG |
Domain
Binds FRP via the C-terminal domain (residues 170-317) (PubMed:23716688).
Upon RCP generation the carotenoid translocates 12 Angstroms into the N-terminal domain, altering its binding and photochemical properties (PubMed:26113721).
Upon RCP generation the carotenoid translocates 12 Angstroms into the N-terminal domain, altering its binding and photochemical properties (PubMed:26113721).
Sequence similarities
Belongs to the orange carotenoid-binding protein family.
Phylogenomic databases
Family and domain databases
Sequence
- Sequence statusComplete
- Length317
- Mass (Da)34,659
- Last updated1997-02-01 v1
- Checksum8FF633BDE6D530F2
Features
Showing features for sequence conflict.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Sequence conflict | 73 | in Ref. 1; AA sequence | ||||
Sequence: A → G | ||||||
Sequence conflict | 75 | in Ref. 1; AA sequence | ||||
Sequence: G → T | ||||||
Sequence conflict | 121 | in Ref. 1; AA sequence | ||||
Sequence: F → L | ||||||
Sequence conflict | 165 | in Ref. 1; AA sequence | ||||
Sequence: A → V | ||||||
Sequence conflict | 169 | in Ref. 1; AA sequence | ||||
Sequence: G → I |
Mass Spectrometry
Orange carotenoid-binding protein
Molecular mass is 34,622 Da. Determined by MALDI. OCP.Red carotenoid-binding protein
Molecular mass is 16,739 Da. Determined by MALDI. RCP.Keywords
- Technical term
Sequence databases
Nucleotide Sequence | Protein Sequence | Molecule Type | Status | |
---|---|---|---|---|
BA000022 EMBL· GenBank· DDBJ | BAA18188.1 EMBL· GenBank· DDBJ | Genomic DNA |