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Protein

CRISPR system Cascade subunit CasB

Gene

casB

Organism
Escherichia coli (strain K12)
Status
Reviewed-Annotation score: Annotation score: 5 out of 5-Experimental evidence at protein leveli

Functioni

CRISPR (clustered regularly interspaced short palindromic repeat), is an adaptive immune system that provides protection against mobile genetic elements (viruses, transposable elements and conjugative plasmids). CRISPR clusters contain sequences complementary to antecedent mobile elements and target invading nucleic acids. CRISPR clusters are transcribed and processed into CRISPR RNA (crRNA).
A component of Cascade, which participates in CRISPR interference, the third stage of CRISPR immunity. Cascade binds both crRNA and in a sequence-specific manner negatively supercoiled dsDNA target. This leads to the formation of an R-loop in which the crRNA binds the target DNA, displacing the noncomplementary strand. Cas3 is recruited to Cascade, nicks target DNA and then unwinds and cleaves the target, leading to DNA degradation and invader neutralization.

GO - Molecular functioni

  • DNA binding Source: EcoCyc
  • RNA binding Source: UniProtKB-KW

GO - Biological processi

  • defense response to virus Source: EcoCyc
Complete GO annotation...

Keywords - Biological processi

Antiviral defense

Keywords - Ligandi

RNA-binding

Enzyme and pathway databases

BioCyciEcoCyc:G7429-MONOMER.
ECOL316407:JW2729-MONOMER.
MetaCyc:G7429-MONOMER.

Names & Taxonomyi

Protein namesi
Recommended name:
CRISPR system Cascade subunit CasB
Gene namesi
Name:casB
Synonyms:cse2, ygcK
Ordered Locus Names:b2759, JW2729
OrganismiEscherichia coli (strain K12)
Taxonomic identifieri83333 [NCBI]
Taxonomic lineageiBacteriaProteobacteriaGammaproteobacteriaEnterobacterialesEnterobacteriaceaeEscherichia
Proteomesi
  • UP000000318 Componenti: Chromosome
  • UP000000625 Componenti: Chromosome

Organism-specific databases

EcoGeneiEG13118. casB.

Subcellular locationi

GO - Cellular componenti

  • protein complex Source: EcoCyc
Complete GO annotation...

Pathology & Biotechi

Disruption phenotypei

Loss of resistance to bacteriophage lambda infection, loss of plasmid silencing. Increased levels of 57 nucleotide crRNA and also 2 and 3 spacer-repeat units.3 Publications

PTM / Processingi

Molecule processing

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Chaini1 – 160160CRISPR system Cascade subunit CasBPRO_0000169323Add
BLAST

Proteomic databases

PaxDbiP76632.
PRIDEiP76632.

Expressioni

Inductioni

Repressed by H-NS, activated by LeuO. Activated by the BaeSR two-component regulatory system, possibly due to envelope stress. Part of the casABCDE-ygbT-ygbF operon.3 Publications

Interactioni

Subunit structurei

Homodimer. Part of the Cascade ribonucleoprotein complex, with stoichiometry CasA1,CasB2, CasC6,CasD1,CasE(1)-crRNA1. The CasB homodimer forms a cleft that cradles the 3' end of the crRNA. Interacts directly with crRNA, CasA, CasC and CasE. Stable subcomplexes of CasBCDE-crRNA and CasCDE-crRNA also form, both of which are able to bind target dsDNA. Binding of target ssRNA or dsDNA causes a conformational change in the Cascade complex.5 Publications

Protein-protein interaction databases

BioGridi4260739. 180 interactions.
DIPiDIP-12127N.
IntActiP76632. 9 interactions.
STRINGi511145.b2759.

Structurei

Secondary structure

1
160
Legend: HelixTurnBeta strand
Show more details
Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Helixi7 – 1610Combined sources
Helixi19 – 268Combined sources
Helixi31 – 366Combined sources
Helixi38 – 447Combined sources
Helixi45 – 473Combined sources
Turni48 – 503Combined sources
Helixi52 – 6514Combined sources
Beta strandi69 – 746Combined sources
Beta strandi79 – 835Combined sources
Helixi87 – 948Combined sources
Helixi99 – 1068Combined sources
Helixi112 – 12413Combined sources
Helixi130 – 1389Combined sources
Helixi142 – 15817Combined sources

3D structure databases

Select the link destinations:
PDBei
RCSB PDBi
PDBji
Links Updated
EntryMethodResolution (Å)ChainPositionsPDBsum
4QYZX-ray3.03B/C1-160[»]
4TVXX-ray3.24J/K/V/W1-160[»]
4U7UX-ray3.00B/C/N/O1-160[»]
5CD4X-ray3.20J/K/V/W1-160[»]
5H9EX-ray3.21B/C1-160[»]
5H9FX-ray2.45B/C1-160[»]
ProteinModelPortaliP76632.
SMRiP76632. Positions 3-159.
ModBaseiSearch...
MobiDBiSearch...

Family & Domainsi

Sequence similaritiesi

Belongs to the CRISPR-associated CasB/Cse2 family.Curated

Phylogenomic databases

eggNOGiENOG41061HK. Bacteria.
ENOG41126UY. LUCA.
HOGENOMiHOG000009769.
InParanoidiP76632.
KOiK19046.
OMAiQNWSELD.

Family and domain databases

CDDicd09670. Cse2_I-E. 1 hit.
InterProiIPR013382. CRISPR-assoc_prot_Cse2.
[Graphical view]
PfamiPF09485. CRISPR_Cse2. 1 hit.
[Graphical view]
TIGRFAMsiTIGR02548. casB_cse2. 1 hit.

Sequencei

Sequence statusi: Complete.

P76632-1 [UniParc]FASTAAdd to basket

« Hide

        10         20         30         40         50
MADEIDAMAL YRAWQQLDNG SCAQIRRVSE PDELRDIPAF YRLVQPFGWE
60 70 80 90 100
NPRHQQALLR MVFCLSAGKN VIRHQDKKSE QTTGISLGRA LANSGRINER
110 120 130 140 150
RIFQLIRADR TADMVQLRRL LTHAEPVLDW PLMARMLTWW GKRERQQLLE
160
DFVLTTNKNA
Length:160
Mass (Da):18,702
Last modified:February 1, 1997 - v1
Checksum:iF2493AAD46595E5C
GO

Sequence cautioni

The sequence AAA69269 differs from that shown. Reason: Frameshift at position 130. Curated

Mass spectrometryi

Molecular mass is 21261.5±1.1 Da from positions 1 - 160. 1 Publication

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
U29579 Genomic DNA. Translation: AAA69269.1. Frameshift.
U00096 Genomic DNA. Translation: AAC75801.1.
AP009048 Genomic DNA. Translation: BAE76836.1.
PIRiC65057.
RefSeqiNP_417239.1. NC_000913.3.
WP_000752800.1. NZ_LN832404.1.

Genome annotation databases

EnsemblBacteriaiAAC75801; AAC75801; b2759.
BAE76836; BAE76836; BAE76836.
GeneIDi947223.
KEGGiecj:JW2729.
eco:b2759.
PATRICi32120928. VBIEscCol129921_2856.

Cross-referencesi

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
U29579 Genomic DNA. Translation: AAA69269.1. Frameshift.
U00096 Genomic DNA. Translation: AAC75801.1.
AP009048 Genomic DNA. Translation: BAE76836.1.
PIRiC65057.
RefSeqiNP_417239.1. NC_000913.3.
WP_000752800.1. NZ_LN832404.1.

3D structure databases

Select the link destinations:
PDBei
RCSB PDBi
PDBji
Links Updated
EntryMethodResolution (Å)ChainPositionsPDBsum
4QYZX-ray3.03B/C1-160[»]
4TVXX-ray3.24J/K/V/W1-160[»]
4U7UX-ray3.00B/C/N/O1-160[»]
5CD4X-ray3.20J/K/V/W1-160[»]
5H9EX-ray3.21B/C1-160[»]
5H9FX-ray2.45B/C1-160[»]
ProteinModelPortaliP76632.
SMRiP76632. Positions 3-159.
ModBaseiSearch...
MobiDBiSearch...

Protein-protein interaction databases

BioGridi4260739. 180 interactions.
DIPiDIP-12127N.
IntActiP76632. 9 interactions.
STRINGi511145.b2759.

Proteomic databases

PaxDbiP76632.
PRIDEiP76632.

Protocols and materials databases

Structural Biology KnowledgebaseSearch...

Genome annotation databases

EnsemblBacteriaiAAC75801; AAC75801; b2759.
BAE76836; BAE76836; BAE76836.
GeneIDi947223.
KEGGiecj:JW2729.
eco:b2759.
PATRICi32120928. VBIEscCol129921_2856.

Organism-specific databases

EchoBASEiEB2919.
EcoGeneiEG13118. casB.

Phylogenomic databases

eggNOGiENOG41061HK. Bacteria.
ENOG41126UY. LUCA.
HOGENOMiHOG000009769.
InParanoidiP76632.
KOiK19046.
OMAiQNWSELD.

Enzyme and pathway databases

BioCyciEcoCyc:G7429-MONOMER.
ECOL316407:JW2729-MONOMER.
MetaCyc:G7429-MONOMER.

Miscellaneous databases

PROiP76632.

Family and domain databases

CDDicd09670. Cse2_I-E. 1 hit.
InterProiIPR013382. CRISPR-assoc_prot_Cse2.
[Graphical view]
PfamiPF09485. CRISPR_Cse2. 1 hit.
[Graphical view]
TIGRFAMsiTIGR02548. casB_cse2. 1 hit.
ProtoNetiSearch...

Entry informationi

Entry nameiCSE2_ECOLI
AccessioniPrimary (citable) accession number: P76632
Secondary accession number(s): Q2MA70, Q46900
Entry historyi
Integrated into UniProtKB/Swiss-Prot: November 1, 1997
Last sequence update: February 1, 1997
Last modified: September 7, 2016
This is version 93 of the entry and version 1 of the sequence. [Complete history]
Entry statusiReviewed (UniProtKB/Swiss-Prot)
Annotation programProkaryotic Protein Annotation Program

Miscellaneousi

Keywords - Technical termi

3D-structure, Complete proteome, Reference proteome

Documents

  1. Escherichia coli
    Escherichia coli (strain K12): entries and cross-references to EcoGene
  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.