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Protein

Repressor protein cI

Gene

cI

Organism
Escherichia phage lambda (Bacteriophage lambda)
Status
Reviewed-Annotation score: Annotation score: 5 out of 5-Experimental evidence at protein leveli

Functioni

Acts as a transcriptional repressor that allows virus to establish and maintain latency. Prevents both the viral DNA replication and the exit programs. Clamps the two operator OL (operator left made of OL1, OL2 and OL3 sites) and OR (operator right made of OR1, OR2 and OR3 sites) together by binding to them and arranging the intervening DNA in a loop. This step allows repression of lytic pR and pL promoters by binding to OL1, OL2, OR1 and OR2 simultaneously. The binding of cI on OR2 additionally activates the transcription of the cI gene thereby mediating an autoregulatory function to maintain the latent state. Once cI is present in sufficient amount, it can repress its own transcription by binding to OL3 and OR3.2 Publications

Miscellaneous

Bacterial cells harboring a lysogenic lambda phage are immune to further infection by lambda. The cI repressor protein inhibits the lytic development of any additional infecting phage particles. The region of the genome that codes for the cI repressor protein is known as the immunity region.

Regions

Feature keyPosition(s)DescriptionActionsGraphical viewLength
DNA bindingi30 – 49H-T-H motifPROSITE-ProRule annotationAdd BLAST20

GO - Molecular functioni

  • core promoter binding Source: CAFA
  • identical protein binding Source: IntAct
  • sequence-specific DNA binding Source: InterPro

GO - Biological processi

  • latency-replication decision Source: UniProtKB-KW
  • maintenance of viral latency Source: CAFA
  • negative regulation of transcription by competitive promoter binding Source: CAFA
  • positive regulation of viral transcription Source: CAFA
  • transcription, DNA-templated Source: UniProtKB-KW

Keywordsi

Molecular functionDNA-binding, Repressor
Biological processLatency-replication decision, Transcription, Transcription regulation, Viral latency, Viral latency initiation and maintenance

Protein family/group databases

MEROPSiS24.002.

Names & Taxonomyi

Protein namesi
Recommended name:
Repressor protein cI
Gene namesi
Name:cI
Ordered Locus Names:lambdap88
OrganismiEscherichia phage lambda (Bacteriophage lambda)
Taxonomic identifieri10710 [NCBI]
Taxonomic lineageiVirusesdsDNA viruses, no RNA stageCaudoviralesSiphoviridaeLambdavirus
Virus hostiEscherichia coli [TaxID: 562]
Proteomesi
  • UP000001711 Componenti: Genome

Subcellular locationi

GO - Cellular componenti

  • virion Source: CAFA

PTM / Processingi

Molecule processing

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Initiator methionineiRemoved; by host1 Publication
ChainiPRO_00001497152 – 237Repressor protein cIAdd BLAST236

Interactioni

Subunit structurei

Homooctamer. The DNA loop is maintained by octamers of repressor cI.

Binary interactionsi

WithEntry#Exp.IntActNotes
itself2EBI-4478303,EBI-4478303

GO - Molecular functioni

  • identical protein binding Source: IntAct

Protein-protein interaction databases

DIPiDIP-17006N.
IntActiP03034. 2 interactors.

Structurei

Secondary structure

1237
Legend: HelixTurnBeta strandPDB Structure known for this area
Show more details
Feature keyPosition(s)DescriptionActionsGraphical viewLength
Helixi10 – 30Combined sources21
Helixi34 – 40Combined sources7
Helixi45 – 52Combined sources8
Helixi60 – 70Combined sources11
Helixi74 – 76Combined sources3
Helixi79 – 85Combined sources7
Turni90 – 92Combined sources3
Beta strandi142 – 145Combined sources4
Beta strandi166 – 170Combined sources5
Beta strandi180 – 184Combined sources5
Beta strandi190 – 198Combined sources9
Beta strandi201 – 205Combined sources5
Beta strandi221 – 230Combined sources10
Helixi233 – 236Combined sources4

3D structure databases

Select the link destinations:
PDBei
RCSB PDBi
PDBji
Links Updated
PDB entryMethodResolution (Å)ChainPositionsPDBsum
1F39X-ray1.90A/B137-237[»]
1GFXmodel-A/B/C/D1-237[»]
1J5Gmodel-A/B/C/D1-237[»]
1KCAX-ray2.91A/B/C/D/E/F/G/H133-237[»]
1LLIX-ray2.10A/B2-93[»]
1LMBX-ray1.803/42-93[»]
1LRPX-ray3.20A/B/C2-93[»]
1LWQmodel-A/B/C/D1-237[»]
1RIOX-ray2.30A/B1-92[»]
3BDNX-ray3.91A/B2-237[»]
3KZ3X-ray1.64A/B8-85[»]
3WOAX-ray2.00A1-46[»]
ProteinModelPortaliP03034.
SMRiP03034.
ModBaseiSearch...
MobiDBiSearch...

Miscellaneous databases

EvolutionaryTraceiP03034.

Family & Domainsi

Domains and Repeats

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Domaini19 – 77HTH cro/C1-typePROSITE-ProRule annotationAdd BLAST59

Phylogenomic databases

OrthoDBiVOG090000SH.

Family and domain databases

CDDicd00093. HTH_XRE. 1 hit.
InterProiView protein in InterPro
IPR001387. Cro/C1-type_HTH.
IPR010982. Lambda_DNA-bd_dom_sf.
IPR036286. LexA/Signal_pep-like_sf.
IPR015927. Peptidase_S24_S26A/B/C.
PfamiView protein in Pfam
PF01381. HTH_3. 1 hit.
PF00717. Peptidase_S24. 1 hit.
SMARTiView protein in SMART
SM00530. HTH_XRE. 1 hit.
SUPFAMiSSF47413. SSF47413. 1 hit.
SSF51306. SSF51306. 1 hit.
PROSITEiView protein in PROSITE
PS50943. HTH_CROC1. 1 hit.

Sequencei

Sequence statusi: Complete.

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

P03034-1 [UniParc]FASTAAdd to basket

« Hide

        10         20         30         40         50
MSTKKKPLTQ EQLEDARRLK AIYEKKKNEL GLSQESVADK MGMGQSGVGA
60 70 80 90 100
LFNGINALNA YNAALLAKIL KVSVEEFSPS IAREIYEMYE AVSMQPSLRS
110 120 130 140 150
EYEYPVFSHV QAGMFSPELR TFTKGDAERW VSTTKKASDS AFWLEVEGNS
160 170 180 190 200
MTAPTGSKPS FPDGMLILVD PEQAVEPGDF CIARLGGDEF TFKKLIRDSG
210 220 230
QVFLQPLNPQ YPMIPCNESC SVVGKVIASQ WPEETFG
Length:237
Mass (Da):26,212
Last modified:January 23, 2007 - v2
Checksum:i4785A4915479ED97
GO

Experimental Info

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Sequence conflicti67A → T (PubMed:714163).Curated1
Sequence conflicti118E → K (PubMed:714163).Curated1

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
J02459 Genomic DNA. Translation: AAA96581.1.
X00166 Genomic DNA. Translation: CAA24991.1.
PIRiA14086. RPBPL.
RefSeqiNP_040628.1. NC_001416.1.

Genome annotation databases

GeneIDi2703537.
KEGGivg:3827059.

Similar proteinsi

Entry informationi

Entry nameiRPC1_LAMBD
AccessioniPrimary (citable) accession number: P03034
Entry historyiIntegrated into UniProtKB/Swiss-Prot: July 21, 1986
Last sequence update: January 23, 2007
Last modified: November 22, 2017
This is version 134 of the entry and version 2 of the sequence. See complete history.
Entry statusiReviewed (UniProtKB/Swiss-Prot)
Annotation programViral Protein Annotation Program

Miscellaneousi

Keywords - Technical termi

3D-structure, Complete proteome, Direct protein sequencing, Reference proteome

Documents

  1. PDB cross-references
    Index of Protein Data Bank (PDB) cross-references