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Protein

Signal recognition particle 43 kDa protein, chloroplastic

Gene

CAO

Organism
Arabidopsis thaliana (Mouse-ear cress)
Status
Reviewed-Annotation score: Annotation score: 5 out of 5-Experimental evidence at protein leveli

Functioni

Component of the chloroplast signal recognition particle pathway. Required for post-translational targeting of proteins into the tylakoid membrane but seems to be dispensable for co-translational targeting with a translating ribosome present. May be able to function independently of cpFTSY and FFC/cpSRP54 in targeting LHCPs to the thylakoids. Acts as a highly specific chaperone for LHCPs, preventing aggregation and being able to dissolve aggregates.5 Publications

Sites

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Metal bindingi232Magnesium1

GO - Molecular functioni

  • identical protein binding Source: IntAct
  • metal ion binding Source: UniProtKB-KW

GO - Biological processi

  • protein import into chloroplast thylakoid membrane Source: TAIR
  • response to high light intensity Source: TAIR
Complete GO annotation...

Keywords - Molecular functioni

Ribonucleoprotein

Keywords - Ligandi

Metal-binding

Protein family/group databases

TCDBi3.A.5.1.2. the general secretory pathway (sec) family.

Names & Taxonomyi

Protein namesi
Recommended name:
Signal recognition particle 43 kDa protein, chloroplastic
Alternative name(s):
Chromo protein SRP43
Short name:
CpSRP43
Gene namesi
Name:CAO
Synonyms:CPSRP43
Ordered Locus Names:At2g47450
ORF Names:T30B22.25
OrganismiArabidopsis thaliana (Mouse-ear cress)
Taxonomic identifieri3702 [NCBI]
Taxonomic lineageiEukaryotaViridiplantaeStreptophytaEmbryophytaTracheophytaSpermatophytaMagnoliophytaeudicotyledonsGunneridaePentapetalaerosidsmalvidsBrassicalesBrassicaceaeCamelineaeArabidopsis
Proteomesi
  • UP000006548 Componenti: Chromosome 2

Organism-specific databases

TAIRiAT2G47450.

Subcellular locationi

GO - Cellular componenti

  • chloroplast Source: TAIR
  • chloroplast envelope Source: TAIR
  • chloroplast stroma Source: UniProtKB-SubCell
  • chloroplast thylakoid membrane Source: TAIR
  • signal recognition particle, chloroplast targeting Source: TAIR
  • signal recognition particle, endoplasmic reticulum targeting Source: UniProtKB-KW
Complete GO annotation...

Keywords - Cellular componenti

Chloroplast, Plastid, Signal recognition particle

Pathology & Biotechi

Disruption phenotypei

Plants show a reduced level of the major light-harvesting chlorophyll a/b-binding proteins (LHCPs).1 Publication

Mutagenesis

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Mutagenesisi161R → A: Decreased interaction with LHCP. 1 Publication1
Mutagenesisi192R → A: Decreased interaction with LHCP. 1 Publication1
Mutagenesisi204Y → A: Loss of interaction with LHCP. 1 Publication1
Mutagenesisi226R → A: Decreased interaction with LHCP. 1 Publication1
Mutagenesisi269Y → A: Decreased interaction with ALB3. 1 Publication1
Mutagenesisi291W → A: Decreased interaction with ALB3. 1 Publication1
Mutagenesisi293D → A: Decreased interaction with ALB3. 1 Publication1

PTM / Processingi

Molecule processing

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Transit peptidei1 – 56ChloroplastSequence analysisAdd BLAST56
ChainiPRO_000023846157 – 373Signal recognition particle 43 kDa protein, chloroplasticAdd BLAST317

Proteomic databases

PaxDbiO22265.
PRIDEiO22265.

Expressioni

Tissue specificityi

Expressed in leaves. Detected in roots.2 Publications

Gene expression databases

GenevisibleiO22265. AT.

Interactioni

Subunit structurei

Homodimer. Component of the cpSRP complex, composed of a FFC/cpSRP54 monomer and a CAO/cpSRP43 dimer. Interacts (via chromo domains 2 and 3) with ALB3 (via C-terminus), but not with ALB3L1/ALB4. Can interact simultaneously with ALB3 and FFC/cpSRP54. Interacts with LHCP and LTD.9 Publications

Binary interactionsi

WithEntry#Exp.IntActNotes
itself4EBI-780656,EBI-780656
ALB3Q8LBP410EBI-780656,EBI-1806831
CAB8P274904EBI-780656,EBI-8295162From a different organism.
FFCP3710716EBI-780656,EBI-780642

GO - Molecular functioni

  • identical protein binding Source: IntAct

Protein-protein interaction databases

BioGridi4693. 16 interactors.
DIPiDIP-37639N.
IntActiO22265. 19 interactors.
MINTiMINT-126461.
STRINGi3702.AT2G47450.1.

Structurei

Secondary structure

1373
Legend: HelixTurnBeta strandPDB Structure known for this area
Show more details
Feature keyPosition(s)DescriptionActionsGraphical viewLength
Beta strandi86 – 95Combined sources10
Turni96 – 98Combined sources3
Beta strandi99 – 106Combined sources8
Turni107 – 110Combined sources4
Beta strandi113 – 116Combined sources4
Helixi117 – 119Combined sources3
Helixi122 – 137Combined sources16
Helixi141 – 147Combined sources7
Turni148 – 150Combined sources3
Helixi163 – 170Combined sources8
Helixi173 – 181Combined sources9
Beta strandi191 – 194Combined sources4
Helixi197 – 203Combined sources7
Helixi207 – 216Combined sources10
Helixi230 – 239Combined sources10
Helixi246 – 263Combined sources18
Beta strandi268 – 270Combined sources3
Beta strandi272 – 281Combined sources10
Beta strandi284 – 294Combined sources11
Beta strandi297 – 301Combined sources5
Helixi302 – 304Combined sources3
Helixi307 – 314Combined sources8
Beta strandi317 – 320Combined sources4
Beta strandi322 – 330Combined sources9
Beta strandi332 – 334Combined sources3
Beta strandi337 – 343Combined sources7
Beta strandi344 – 348Combined sources5
Beta strandi350 – 353Combined sources4
Turni354 – 356Combined sources3
Helixi359 – 367Combined sources9

3D structure databases

Select the link destinations:
PDBei
RCSB PDBi
PDBji
Links Updated
PDB entryMethodResolution (Å)ChainPositionsPDBsum
1X32NMR-A84-128[»]
1X3PNMR-A320-373[»]
1X3QNMR-A265-319[»]
2HUGNMR-A265-319[»]
2N88NMR-A316-373[»]
3DEOX-ray1.50A85-267[»]
3DEPX-ray2.70A85-267[»]
3UI2X-ray3.18A84-327[»]
5E4WX-ray2.80C/D265-369[»]
5E4XX-ray2.75A319-368[»]
ProteinModelPortaliO22265.
SMRiO22265.
ModBaseiSearch...
MobiDBiSearch...

Miscellaneous databases

EvolutionaryTraceiO22265.

Family & Domainsi

Domains and Repeats

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Domaini84 – 135Chromo 1PROSITE-ProRule annotationAdd BLAST52
Repeati136 – 158ANK 1Add BLAST23
Repeati159 – 188ANK 2Add BLAST30
Repeati193 – 222ANK 3Add BLAST30
Repeati242 – 269ANK 4Add BLAST28
Domaini270 – 320Chromo 2PROSITE-ProRule annotationAdd BLAST51
Domaini321 – 373Chromo 3PROSITE-ProRule annotationAdd BLAST53

Coiled coil

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Coiled coili57 – 79Sequence analysisAdd BLAST23

Compositional bias

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Compositional biasi79 – 82Poly-Ser4
Compositional biasi366 – 369Poly-Gln4

Domaini

The binding to LHCP occurs through the first ankyrin repeat and the L18 domain of LHCP.
Homodimerization occurs through both the third and the fourth ankyrin repeats.
Chromo domain 1 may act as a negative regulator of GTP hydrolysis by FFC/cpSRP54. It is unnecessary for targeting complex formation but is required for integration into the thylakoid membrane.
Chromo domain 2 is involved in binding to the M domain of FFC/cpSRP54.

Sequence similaritiesi

Contains 4 ANK repeats.PROSITE-ProRule annotation
Contains 3 chromo domains.PROSITE-ProRule annotation

Keywords - Domaini

ANK repeat, Coiled coil, Repeat, Transit peptide

Phylogenomic databases

eggNOGiKOG0504. Eukaryota.
COG0666. LUCA.
HOGENOMiHOG000239692.
KOiK12271.
OMAiMEYLIEW.
OrthoDBiEOG09360GNA.
PhylomeDBiO22265.

Family and domain databases

Gene3Di1.25.40.20. 1 hit.
InterProiIPR002110. Ankyrin_rpt.
IPR020683. Ankyrin_rpt-contain_dom.
IPR000953. Chromo/shadow_dom.
IPR023780. Chromo_domain.
IPR016197. Chromodomain-like.
IPR030300. CPSRP43.
[Graphical view]
PANTHERiPTHR24128:SF11. PTHR24128:SF11. 1 hit.
PfamiPF12796. Ank_2. 1 hit.
PF00385. Chromo. 1 hit.
[Graphical view]
SMARTiSM00248. ANK. 3 hits.
SM00298. CHROMO. 3 hits.
[Graphical view]
SUPFAMiSSF48403. SSF48403. 1 hit.
SSF54160. SSF54160. 3 hits.
PROSITEiPS50297. ANK_REP_REGION. 1 hit.
PS50088. ANK_REPEAT. 2 hits.
PS50013. CHROMO_2. 1 hit.
[Graphical view]

Sequencei

Sequence statusi: Complete.

Sequence processingi: The displayed sequence is further processed into a mature form.

O22265-1 [UniParc]FASTAAdd to basket

« Hide

        10         20         30         40         50
MQKVFLAMDT CALVIHQSLS RIKLSPPKSS SSSSSAFSPE SLPIRRIELC
60 70 80 90 100
FRGAICAAVQ RNYEETTSSV EEAEEDDESS SSYGEVNKII GSRTAGEGAM
110 120 130 140 150
EYLIEWKDGH SPSWVPSSYI AADVVSEYET PWWTAARKAD EQALSQLLED
160 170 180 190 200
RDVDAVDENG RTALLFVAGL GSDKCVRLLA EAGADLDHRD MRGGLTALHM
210 220 230 240 250
AAGYVRPEVV EALVELGADI EVEDERGLTA LELAREILKT TPKGNPMQFG
260 270 280 290 300
RRIGLEKVIN VLEGQVFEYA EVDEIVEKRG KGKDVEYLVR WKDGGDCEWV
310 320 330 340 350
KGVHVAEDVA KDYEDGLEYA VAESVIGKRV GDDGKTIEYL VKWTDMSDAT
360 370
WEPQDNVDST LVLLYQQQQP MNE
Length:373
Mass (Da):41,279
Last modified:June 1, 2002 - v2
Checksum:iF75ED9C7046A1441
GO

Experimental Info

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Sequence conflicti35S → SSSS in AAD01509 (PubMed:9878634).Curated1
Sequence conflicti73A → V in AAK96775 (PubMed:14593172).Curated1
Sequence conflicti73A → V in AAN72202 (PubMed:14593172).Curated1
Sequence conflicti137R → K in AAD01509 (PubMed:9878634).Curated1

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
AF013115 Genomic DNA. Translation: AAD01509.1.
AC002535 Genomic DNA. Translation: AAC62865.2.
CP002685 Genomic DNA. Translation: AEC10842.1.
AY050442 mRNA. Translation: AAK91457.1.
AY054584 mRNA. Translation: AAK96775.1.
AY057532 mRNA. Translation: AAL09772.1.
AY133540 mRNA. Translation: AAM91370.1.
BT002191 mRNA. Translation: AAN72202.1.
PIRiT00439.
RefSeqiNP_566101.1. NM_130313.3.
UniGeneiAt.19748.
At.72297.

Genome annotation databases

EnsemblPlantsiAT2G47450.1; AT2G47450.1; AT2G47450.
GeneIDi819358.
GrameneiAT2G47450.1; AT2G47450.1; AT2G47450.
KEGGiath:AT2G47450.

Cross-referencesi

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
AF013115 Genomic DNA. Translation: AAD01509.1.
AC002535 Genomic DNA. Translation: AAC62865.2.
CP002685 Genomic DNA. Translation: AEC10842.1.
AY050442 mRNA. Translation: AAK91457.1.
AY054584 mRNA. Translation: AAK96775.1.
AY057532 mRNA. Translation: AAL09772.1.
AY133540 mRNA. Translation: AAM91370.1.
BT002191 mRNA. Translation: AAN72202.1.
PIRiT00439.
RefSeqiNP_566101.1. NM_130313.3.
UniGeneiAt.19748.
At.72297.

3D structure databases

Select the link destinations:
PDBei
RCSB PDBi
PDBji
Links Updated
PDB entryMethodResolution (Å)ChainPositionsPDBsum
1X32NMR-A84-128[»]
1X3PNMR-A320-373[»]
1X3QNMR-A265-319[»]
2HUGNMR-A265-319[»]
2N88NMR-A316-373[»]
3DEOX-ray1.50A85-267[»]
3DEPX-ray2.70A85-267[»]
3UI2X-ray3.18A84-327[»]
5E4WX-ray2.80C/D265-369[»]
5E4XX-ray2.75A319-368[»]
ProteinModelPortaliO22265.
SMRiO22265.
ModBaseiSearch...
MobiDBiSearch...

Protein-protein interaction databases

BioGridi4693. 16 interactors.
DIPiDIP-37639N.
IntActiO22265. 19 interactors.
MINTiMINT-126461.
STRINGi3702.AT2G47450.1.

Protein family/group databases

TCDBi3.A.5.1.2. the general secretory pathway (sec) family.

Proteomic databases

PaxDbiO22265.
PRIDEiO22265.

Protocols and materials databases

Structural Biology KnowledgebaseSearch...

Genome annotation databases

EnsemblPlantsiAT2G47450.1; AT2G47450.1; AT2G47450.
GeneIDi819358.
GrameneiAT2G47450.1; AT2G47450.1; AT2G47450.
KEGGiath:AT2G47450.

Organism-specific databases

TAIRiAT2G47450.

Phylogenomic databases

eggNOGiKOG0504. Eukaryota.
COG0666. LUCA.
HOGENOMiHOG000239692.
KOiK12271.
OMAiMEYLIEW.
OrthoDBiEOG09360GNA.
PhylomeDBiO22265.

Miscellaneous databases

EvolutionaryTraceiO22265.
PROiO22265.

Gene expression databases

GenevisibleiO22265. AT.

Family and domain databases

Gene3Di1.25.40.20. 1 hit.
InterProiIPR002110. Ankyrin_rpt.
IPR020683. Ankyrin_rpt-contain_dom.
IPR000953. Chromo/shadow_dom.
IPR023780. Chromo_domain.
IPR016197. Chromodomain-like.
IPR030300. CPSRP43.
[Graphical view]
PANTHERiPTHR24128:SF11. PTHR24128:SF11. 1 hit.
PfamiPF12796. Ank_2. 1 hit.
PF00385. Chromo. 1 hit.
[Graphical view]
SMARTiSM00248. ANK. 3 hits.
SM00298. CHROMO. 3 hits.
[Graphical view]
SUPFAMiSSF48403. SSF48403. 1 hit.
SSF54160. SSF54160. 3 hits.
PROSITEiPS50297. ANK_REP_REGION. 1 hit.
PS50088. ANK_REPEAT. 2 hits.
PS50013. CHROMO_2. 1 hit.
[Graphical view]
ProtoNetiSearch...

Entry informationi

Entry nameiSR43C_ARATH
AccessioniPrimary (citable) accession number: O22265
Secondary accession number(s): Q93V50, Q940I7, Q9SAU3
Entry historyi
Integrated into UniProtKB/Swiss-Prot: May 30, 2006
Last sequence update: June 1, 2002
Last modified: November 30, 2016
This is version 140 of the entry and version 2 of the sequence. [Complete history]
Entry statusiReviewed (UniProtKB/Swiss-Prot)
Annotation programPlant Protein Annotation Program

Miscellaneousi

Miscellaneous

Unlike eukaryotic or prokaryotic signal recognition particle (SRP), the chloroplast SRP from higher plants lacks an SRP-RNA component. It targets both chloroplast-encoded and nucleus-encoded substrates to the thylakoid membrane, post-translationally for the nucleus-encoded proteins and co-translationally for the chloroplast-encoded proteins.

Keywords - Technical termi

3D-structure, Complete proteome, Reference proteome

Documents

  1. Arabidopsis thaliana
    Arabidopsis thaliana: entries and gene names
  2. PDB cross-references
    Index of Protein Data Bank (PDB) cross-references
  3. SIMILARITY comments
    Index of protein domains and families

Similar proteinsi

Links to similar proteins from the UniProt Reference Clusters (UniRef) at 100%, 90% and 50% sequence identity:
100%UniRef100 combines identical sequences and sub-fragments with 11 or more residues from any organism into one UniRef entry.
90%UniRef90 is built by clustering UniRef100 sequences that have at least 90% sequence identity to, and 80% overlap with, the longest sequence (a.k.a seed sequence).
50%UniRef50 is built by clustering UniRef90 seed sequences that have at least 50% sequence identity to, and 80% overlap with, the longest sequence in the cluster.