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Protein

CRISPR system Cascade subunit CasB

Gene

casB

Organism
Escherichia coli (strain K12)
Status
Reviewed-Annotation score: -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
  • nucleic acid binding Source: EcoCyc
  • RNA binding Source: UniProtKB-KW

GO - Biological processi

  • defense response to virus Source: EcoCyc

Keywordsi

Molecular functionRNA-binding
Biological processAntiviral defense

Enzyme and pathway databases

BioCyciEcoCyc:G7429-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 lineageiBacteriaProteobacteriaGammaproteobacteriaEnterobacteralesEnterobacteriaceaeEscherichia
Proteomesi
  • UP000000318 Componenti: Chromosome
  • UP000000625 Componenti: Chromosome

Organism-specific databases

EcoGeneiEG13118 casB

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)DescriptionActionsGraphical viewLength
ChainiPRO_00001693231 – 160CRISPR system Cascade subunit CasBAdd BLAST160

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,CasE1-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 interactors
ComplexPortaliCPX-1005 Cascade complex
DIPiDIP-12127N
IntActiP76632, 13 interactors
STRINGi316385.ECDH10B_2927

Structurei

Secondary structure

1160
Legend: HelixTurnBeta strandPDB Structure known for this area
Show more details
Feature keyPosition(s)DescriptionActionsGraphical viewLength
Helixi7 – 16Combined sources10
Helixi19 – 26Combined sources8
Helixi31 – 36Combined sources6
Helixi38 – 44Combined sources7
Helixi45 – 47Combined sources3
Turni48 – 50Combined sources3
Helixi52 – 65Combined sources14
Beta strandi69 – 74Combined sources6
Beta strandi79 – 83Combined sources5
Helixi87 – 94Combined sources8
Helixi99 – 106Combined sources8
Helixi112 – 124Combined sources13
Helixi130 – 138Combined sources9
Helixi142 – 158Combined sources17

3D structure databases

Select the link destinations:
PDBei
RCSB PDBi
PDBji
Links Updated
PDB 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
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
Gene3Di1.10.520.40, 1 hit
InterProiView protein in InterPro
IPR013382 CRISPR-assoc_prot_Cse2
IPR038287 Cse2_sf
PfamiView protein in Pfam
PF09485 CRISPR_Cse2, 1 hit
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
PATRICifig|1411691.4.peg.3979

Similar proteinsi

Entry informationi

Entry nameiCSE2_ECOLI
AccessioniPrimary (citable) accession number: P76632
Secondary accession number(s): Q2MA70, Q46900
Entry historyiIntegrated into UniProtKB/Swiss-Prot: November 1, 1997
Last sequence update: February 1, 1997
Last modified: June 20, 2018
This is version 103 of the entry and version 1 of the sequence. See complete history.
Entry statusiReviewed (UniProtKB/Swiss-Prot)
Annotation programProkaryotic Protein Annotation Program

Miscellaneousi

Keywords - Technical termi

3D-structure, Complete proteome, Reference proteome

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