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Protein

CRISPR system Cascade subunit CasA

Gene

casA

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, probably via interactions with CasA, nicks target DNA and then unwinds and cleaves the target, leading to DNA degradation and invader neutralization. CasA is not required for formation of Cascade, but probably enhances binding to and subsequent recognition of both target dsDNA and ssDNA.

GO - Molecular functioni

  • DNA binding Source: EcoCyc
  • RNA binding Source: EcoCyc
  • zinc ion binding Source: EcoCyc

GO - Biological processi

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

Keywords - Biological processi

Antiviral defense

Keywords - Ligandi

DNA-binding, RNA-binding

Enzyme and pathway databases

BioCyciEcoCyc:G7430-MONOMER.
ECOL316407:JW2730-MONOMER.
MetaCyc:G7430-MONOMER.

Names & Taxonomyi

Protein namesi
Recommended name:
CRISPR system Cascade subunit CasA
Alternative name(s):
CRISPR type I-E/Ecoli-associated protein CasA/Cse1
CRISPR-associated protein CasA/Cse1
Gene namesi
Name:casA
Synonyms:cse1, ygcL
Ordered Locus Names:b2760, JW2730
OrganismiEscherichia coli (strain K12)
Taxonomic identifieri83333 [NCBI]
Taxonomic lineageiBacteriaProteobacteriaGammaproteobacteriaEnterobacteralesEnterobacteriaceaeEscherichia
Proteomesi
  • UP000000318 Componenti: Chromosome
  • UP000000625 Componenti: Chromosome

Organism-specific databases

EcoGeneiEG13119. casA.

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.3 Publications

Mutagenesis

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Mutagenesisi129F → A: 80% increase in phage sensitivity; 500-fold decrease in affinity for target dsDNA. 1 Publication1
Mutagenesisi130V → A: 20% increase in phage sensitivity; no change in binding of target dsDNA. 1 Publication1
Mutagenesisi131N → A: 45% increase in phage sensitivity; 60-fold decrease in affinity for target dsDNA. 1 Publication1

PTM / Processingi

Molecule processing

Feature keyPosition(s)DescriptionActionsGraphical viewLength
ChainiPRO_00001693241 – 502CRISPR system Cascade subunit CasAAdd BLAST502

Proteomic databases

PaxDbiQ46901.
PRIDEiQ46901.

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.4 Publications

Interactioni

Subunit structurei

Part of the Cascade ribonucleoprotein complex, with stoichiometry CasA1,CasB2,CasC6,CasD1,CasE(1)-crRNA1. Interacts directly with the 5' end of crRNA, CasB, CasD and CasE. Binding of target ssRNA or dsDNA causes a conformational change in the Cascade complex; CasA is required for high affinity target DNA binding. Interacts with Cas3 once Cascade has recognized target DNA.5 Publications

Protein-protein interaction databases

BioGridi4260748. 358 interactors.
DIPiDIP-12128N.
IntActiQ46901. 6 interactors.
STRINGi511145.b2760.

Structurei

Secondary structure

1502
Legend: HelixTurnBeta strandPDB Structure known for this area
Show more details
Feature keyPosition(s)DescriptionActionsGraphical viewLength
Turni3 – 5Combined sources3
Beta strandi9 – 13Combined sources5
Beta strandi20 – 22Combined sources3
Helixi24 – 28Combined sources5
Beta strandi34 – 36Combined sources3
Helixi41 – 58Combined sources18
Helixi64 – 72Combined sources9
Helixi77 – 84Combined sources8
Helixi85 – 90Combined sources6
Beta strandi92 – 94Combined sources3
Helixi114 – 117Combined sources4
Beta strandi121 – 124Combined sources4
Helixi127 – 130Combined sources4
Beta strandi137 – 139Combined sources3
Helixi141 – 153Combined sources13
Beta strandi173 – 176Combined sources4
Helixi181 – 187Combined sources7
Helixi192 – 198Combined sources7
Turni210 – 212Combined sources3
Beta strandi220 – 222Combined sources3
Helixi223 – 225Combined sources3
Helixi228 – 232Combined sources5
Beta strandi237 – 241Combined sources5
Beta strandi247 – 249Combined sources3
Turni251 – 253Combined sources3
Beta strandi256 – 258Combined sources3
Beta strandi264 – 267Combined sources4
Beta strandi272 – 275Combined sources4
Beta strandi280 – 282Combined sources3
Beta strandi284 – 289Combined sources6
Beta strandi292 – 297Combined sources6
Turni308 – 310Combined sources3
Helixi311 – 321Combined sources11
Beta strandi324 – 326Combined sources3
Helixi329 – 337Combined sources9
Beta strandi345 – 353Combined sources9
Beta strandi356 – 363Combined sources8
Helixi369 – 372Combined sources4
Helixi376 – 405Combined sources30
Helixi411 – 414Combined sources4
Helixi415 – 428Combined sources14
Helixi431 – 437Combined sources7
Turni440 – 442Combined sources3
Helixi443 – 466Combined sources24
Helixi467 – 469Combined sources3
Helixi473 – 475Combined sources3
Helixi476 – 491Combined sources16

3D structure databases

Select the link destinations:
PDBei
RCSB PDBi
PDBji
Links Updated
PDB entryMethodResolution (Å)ChainPositionsPDBsum
4QYZX-ray3.03A1-502[»]
4TVXX-ray3.24I/U1-502[»]
4U7UX-ray3.00A/M1-502[»]
5CD4X-ray3.20I/U1-502[»]
5H9EX-ray3.21A1-502[»]
5H9FX-ray2.45A1-502[»]
ProteinModelPortaliQ46901.
SMRiQ46901.
ModBaseiSearch...
MobiDBiSearch...

Family & Domainsi

Sequence similaritiesi

Phylogenomic databases

eggNOGiENOG4105CYR. Bacteria.
ENOG410XPCD. LUCA.
HOGENOMiHOG000009770.
InParanoidiQ46901.
KOiK19123.
OMAiTPITTFV.

Family and domain databases

CDDicd09669. Cse1_I-E. 1 hit.
InterProiIPR013381. CRISPR-assoc_prot_Cse1.
[Graphical view]
PfamiPF09481. CRISPR_Cse1. 1 hit.
[Graphical view]
TIGRFAMsiTIGR02547. casA_cse1. 1 hit.

Sequencei

Sequence statusi: Complete.

Q46901-1 [UniParc]FASTAAdd to basket

« Hide

        10         20         30         40         50
MNLLIDNWIP VRPRNGGKVQ IINLQSLYCS RDQWRLSLPR DDMELAALAL
60 70 80 90 100
LVCIGQIIAP AKDDVEFRHR IMNPLTEDEF QQLIAPWIDM FYLNHAEHPF
110 120 130 140 150
MQTKGVKAND VTPMEKLLAG VSGATNCAFV NQPGQGEALC GGCTAIALFN
160 170 180 190 200
QANQAPGFGG GFKSGLRGGT PVTTFVRGID LRSTVLLNVL TLPRLQKQFP
210 220 230 240 250
NESHTENQPT WIKPIKSNES IPASSIGFVR GLFWQPAHIE LCDPIGIGKC
260 270 280 290 300
SCCGQESNLR YTGFLKEKFT FTVNGLWPHP HSPCLVTVKK GEVEEKFLAF
310 320 330 340 350
TTSAPSWTQI SRVVVDKIIQ NENGNRVAAV VNQFRNIAPQ SPLELIMGGY
360 370 380 390 400
RNNQASILER RHDVLMFNQG WQQYGNVINE IVTVGLGYKT ALRKALYTFA
410 420 430 440 450
EGFKNKDFKG AGVSVHETAE RHFYRQSELL IPDVLANVNF SQADEVIADL
460 470 480 490 500
RDKLHQLCEM LFNQSVAPYA HHPKLISTLA LARATLYKHL RELKPQGGPS

NG
Length:502
Mass (Da):55,901
Last modified:November 1, 1996 - v1
Checksum:iB3ACC755ABE8D965
GO

Mass spectrometryi

Molecular mass is 55972.4±14.8 Da from positions 1 - 502. 1 Publication

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
U29579 Genomic DNA. Translation: AAA69270.1.
U00096 Genomic DNA. Translation: AAC75802.1.
AP009048 Genomic DNA. Translation: BAE76837.1.
PIRiD65057.
RefSeqiNP_417240.1. NC_000913.3.
WP_001050401.1. NZ_LN832404.1.

Genome annotation databases

EnsemblBacteriaiAAC75802; AAC75802; b2760.
BAE76837; BAE76837; BAE76837.
GeneIDi947222.
KEGGiecj:JW2730.
eco:b2760.
PATRICi32120930. VBIEscCol129921_2857.

Cross-referencesi

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
U29579 Genomic DNA. Translation: AAA69270.1.
U00096 Genomic DNA. Translation: AAC75802.1.
AP009048 Genomic DNA. Translation: BAE76837.1.
PIRiD65057.
RefSeqiNP_417240.1. NC_000913.3.
WP_001050401.1. NZ_LN832404.1.

3D structure databases

Select the link destinations:
PDBei
RCSB PDBi
PDBji
Links Updated
PDB entryMethodResolution (Å)ChainPositionsPDBsum
4QYZX-ray3.03A1-502[»]
4TVXX-ray3.24I/U1-502[»]
4U7UX-ray3.00A/M1-502[»]
5CD4X-ray3.20I/U1-502[»]
5H9EX-ray3.21A1-502[»]
5H9FX-ray2.45A1-502[»]
ProteinModelPortaliQ46901.
SMRiQ46901.
ModBaseiSearch...
MobiDBiSearch...

Protein-protein interaction databases

BioGridi4260748. 358 interactors.
DIPiDIP-12128N.
IntActiQ46901. 6 interactors.
STRINGi511145.b2760.

Proteomic databases

PaxDbiQ46901.
PRIDEiQ46901.

Protocols and materials databases

Structural Biology KnowledgebaseSearch...

Genome annotation databases

EnsemblBacteriaiAAC75802; AAC75802; b2760.
BAE76837; BAE76837; BAE76837.
GeneIDi947222.
KEGGiecj:JW2730.
eco:b2760.
PATRICi32120930. VBIEscCol129921_2857.

Organism-specific databases

EchoBASEiEB2920.
EcoGeneiEG13119. casA.

Phylogenomic databases

eggNOGiENOG4105CYR. Bacteria.
ENOG410XPCD. LUCA.
HOGENOMiHOG000009770.
InParanoidiQ46901.
KOiK19123.
OMAiTPITTFV.

Enzyme and pathway databases

BioCyciEcoCyc:G7430-MONOMER.
ECOL316407:JW2730-MONOMER.
MetaCyc:G7430-MONOMER.

Miscellaneous databases

PROiQ46901.

Family and domain databases

CDDicd09669. Cse1_I-E. 1 hit.
InterProiIPR013381. CRISPR-assoc_prot_Cse1.
[Graphical view]
PfamiPF09481. CRISPR_Cse1. 1 hit.
[Graphical view]
TIGRFAMsiTIGR02547. casA_cse1. 1 hit.
ProtoNetiSearch...

Entry informationi

Entry nameiCSE1_ECOLI
AccessioniPrimary (citable) accession number: Q46901
Secondary accession number(s): Q2MA69
Entry historyi
Integrated into UniProtKB/Swiss-Prot: December 1, 2000
Last sequence update: November 1, 1996
Last modified: November 2, 2016
This is version 96 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.