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Protein

Signal recognition particle 43 kDa protein, chloroplastic

Gene

CAO

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

Functioni

Component of the chloroplast signal recognition particle pathway. Required for post-translational targeting of proteins into the thylakoid 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

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.

Sites

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Metal bindingi232Magnesium1

GO - Molecular functioni

  • disordered domain specific binding Source: CAFA
  • identical protein binding Source: IntAct
  • metal ion binding Source: UniProtKB-KW
  • protein binding, bridging Source: CAFA
  • protein domain specific binding Source: CAFA

GO - Biological processi

  • protein heterotrimerization Source: CAFA
  • protein import into chloroplast thylakoid membrane Source: TAIR
  • response to high light intensity Source: TAIR

Keywordsi

Molecular functionRibonucleoprotein
LigandMetal-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

AraportiAT2G47450
TAIRilocus:2062046 AT2G47450

Subcellular locationi

Extracellular region or secreted Cytosol Plasma membrane Cell wall Cytoskeleton Vacuole Chloroplast Endosome Peroxisome ER Golgi apparatus Nucleus Mitochondrion Manual annotation Automatic computational assertion Graphics by Christian Stolte; Source: COMPARTMENTS

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

ExpressionAtlasiO22265 baseline and differential
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

Show more details

GO - Molecular functioni

  • disordered domain specific binding Source: CAFA
  • identical protein binding Source: IntAct
  • protein binding, bridging Source: CAFA
  • protein domain specific binding Source: CAFA

Protein-protein interaction databases

BioGridi4693, 17 interactors
DIPiDIP-37639N
IntActiO22265, 21 interactors
MINTiO22265
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

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.

Keywords - Domaini

ANK repeat, Coiled coil, Repeat, Transit peptide

Phylogenomic databases

eggNOGiKOG0504 Eukaryota
COG0666 LUCA
HOGENOMiHOG000239692
KOiK12271
OMAiDGHAPSW
OrthoDBiEOG09360GNA
PhylomeDBiO22265

Family and domain databases

CDDicd00204 ANK, 1 hit
cd00024 CHROMO, 2 hits
Gene3Di1.25.40.20, 1 hit
InterProiView protein in InterPro
IPR002110 Ankyrin_rpt
IPR020683 Ankyrin_rpt-contain_dom
IPR036770 Ankyrin_rpt-contain_sf
IPR016197 Chromo-like_dom_sf
IPR000953 Chromo/chromo_shadow_dom
IPR023780 Chromo_domain
IPR030300 CPSRP43
PANTHERiPTHR24128:SF11 PTHR24128:SF11, 1 hit
PfamiView protein in Pfam
PF12796 Ank_2, 1 hit
PF00385 Chromo, 1 hit
SMARTiView protein in SMART
SM00248 ANK, 3 hits
SM00298 CHROMO, 3 hits
SUPFAMiSSF48403 SSF48403, 1 hit
SSF54160 SSF54160, 3 hits
PROSITEiView protein in PROSITE
PS50297 ANK_REP_REGION, 1 hit
PS50088 ANK_REPEAT, 2 hits
PS50013 CHROMO_2, 1 hit

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

Similar proteinsi

Entry informationi

Entry nameiSR43C_ARATH
AccessioniPrimary (citable) accession number: O22265
Secondary accession number(s): Q93V50, Q940I7, Q9SAU3
Entry historyiIntegrated into UniProtKB/Swiss-Prot: May 30, 2006
Last sequence update: June 1, 2002
Last modified: April 25, 2018
This is version 152 of the entry and version 2 of the sequence. See complete history.
Entry statusiReviewed (UniProtKB/Swiss-Prot)
Annotation programPlant Protein Annotation Program

Miscellaneousi

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

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