P03527 (SIGM3_REOVD) Reviewed, UniProtKB/Swiss-Prot

Names and origin

Protein names

Recommended name:
Outer capsid protein sigma-3
Short name=Sigma3

Gene names

Name:

S4

Organism

Reovirus type 3 (strain Dearing) (T3D) (Mammalian orthoreovirus 3) [Complete proteome]

Taxonomic identifier

10886 [NCBI]

Taxonomic lineage

Viruses › dsRNA viruses › Reoviridae › Spinareovirinae › Orthoreovirus › Mammalian orthoreovirus › Mammalian orthoreovirus 3

Virus host

Mammalia [TaxID: 40674]

Protein attributes

Sequence length	365 AA.
Sequence status	Complete.
Protein existence	Evidence at protein level

General annotation (Comments)

Function	Stimulates translation by blocking the activation of the dsRNA-dependent protein kinase EIF2AK2/PKR, thereby inhibiting the host interferon response. Sigma3 prevents the activation of EIF2AK2 by competing with the kinase for dsRNA-binding. Ref.4 The viral outer shell polypeptides, of which sigma-3 is one, impose structural constraints that prevent elongation of nascent transcripts by the RNA-dependent RNA polymerase lambda-3 By similarity. Ref.4
Subunit structure	Heterohexamer of three sigma-3 and three Mu-1 proteins By similarity. The RNA-binding form is probably a homodimer.
Subcellular location	Virion. Note: Found in the outer capsid. Each subunit is positioned with the small lobe anchoring it to the protein mu1 on the surface of the virion, and the large lobe, the site of initial cleavages during entry-related proteolytic disassembly, protruding outwards.
Post-translational modification	Cleaved during virus the endosomal proteolytic disassembly of the outer capsid.
Sequence similarities	Belongs to the orthoreovirus sigma-3 protein family. Contains 1 CCHC-type zinc finger.

Ontologies

Keywords
Biological process	Host-virus interaction Inhibition of host PKR by virus Inhibition of host innate immune response by virus Inhibition of host interferon signaling pathway by virus Interferon antiviral system evasion Transcription Transcription regulation Translation regulation Viral immunoevasion
Cellular component	Virion
Domain	Zinc-finger
Ligand	Metal-binding RNA-binding Zinc
Molecular function	Capsid protein
Technical term	3D-structure Complete proteome
Gene Ontology (GO)
Biological_process	regulation of transcription, DNA-dependent Inferred from electronic annotation. Source: UniProtKB-KW regulation of translation Inferred from electronic annotation. Source: UniProtKB-KW suppression by virus of host PKR activity Inferred from electronic annotation. Source: UniProtKB-KW suppression by virus of host type I interferon-mediated signaling pathway Inferred from electronic annotation. Source: UniProtKB-KW transcription, DNA-dependent Inferred from electronic annotation. Source: UniProtKB-KW viral infectious cycle Inferred from electronic annotation. Source: InterPro
Cellular_component	viral capsid Inferred from electronic annotation. Source: UniProtKB-KW
Molecular_function	RNA binding Inferred from electronic annotation. Source: UniProtKB-KW metal ion binding Inferred from electronic annotation. Source: UniProtKB-KW structural molecule activity Inferred from electronic annotation. Source: InterPro
Complete GO annotation...

Sequence annotation (Features)

Feature key

Position(s)

Length

Description

Graphical view

Feature identifier

Molecule processing

Chain

1 – 365

365

Outer capsid protein sigma-3

PRO_0000222752

Regions

Zinc finger

51 – 73

23

CCHC-type

Natural variations

Natural variant

354

1

Y → H in strain: Isolate D-EA1 and Isolate D-EA3; altered susceptibility to proteolysis during virus disassembly.

Experimental info

Sequence conflict

133

1

W → R in AAA47283. Ref.1

Sequence conflict

198

1

G → E in AAA47283. Ref.1

Secondary structure

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365

Helix Strand Turn

Details...

Helix

8 – 18

11

Turn

19 – 21

3

Beta strand

25 – 27

3

Turn

28 – 30

3

Beta strand

41 – 45

5

Beta strand

48 – 51

4

Turn

52 – 54

3

Beta strand

57 – 60

4

Helix

61 – 63

3

Helix

79 – 111

33

Helix

115 – 124

10

Beta strand

126 – 130

5

Helix

133 – 135

3

Turn

141 – 143

3

Helix

159 – 176

18

Beta strand

180 – 186

7

Helix

189 – 192

4

Helix

199 – 203

5

Beta strand

221 – 223

3

Helix

226 – 230

5

Helix

232 – 234

3

Helix

236 – 242

7

Helix

246 – 249

4

Helix

252 – 254

3

Beta strand

259 – 261

3

Beta strand

270 – 272

3

Helix

275 – 277

3

Beta strand

282 – 284

3

Helix

288 – 292

5

Helix

293 – 295

3

Helix

296 – 305

10

Helix

308 – 315

8

Helix

319 – 334

16

Helix

338 – 341

4

Beta strand

351 – 354

4

Beta strand

356 – 358

3

Beta strand

362 – 365

4

Sequences

	Sequence		Length	Mass (Da)
	P03527 [UniParc]. Last modified July 22, 2008. Version 2. Checksum: CF50174AA43244EB	FASTA	365	41,118
	10 20 30 40 50 60 MEVCLPNGHQ VVDLINNAFE GRVSIYSAQE GWDKTISAQP DMMVCGGAVV CMHCLGVVGS 70 80 90 100 110 120 LQRKLKHLPH HRCNQQIRHQ DYVDVQFADR VTAHWKRGML SFVAQMHEMM NDVSPDDLDR 130 140 150 160 170 180 VRTEGGSLVE LNWLQVDPNS MFRSIHSSWT DPLQVVDDLD TKLDQYWTAL NLMIDSSDLI 190 200 210 220 230 240 PNFMMRDPSH AFNGVKLGGD ARQTQFSRTF DSRSSLEWGV MVYDYSELEH DPSKGRAYRK 250 260 270 280 290 300 ELVTPARDFG HFGLSHYSRA TTPILGKMPA VFSGMLTGNC KMYPFIKGTA KLKTVRKLVE 310 320 330 340 350 360 AVNHAWGVEK IRYALGPGGM TGWYNRTMQQ APIVLTPAAL TMFPDTIKFG DLNYPVMIGD PMILG

References

[1]	"Reovirus type 3 genome segment S4: nucleotide sequence of the gene encoding a major virion surface protein." Giantini M., Seliger L.S., Furuichi Y., Shatkin A.J. J. Virol. 52:984-987(1984) [PubMed] [Europe PMC] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [GENOMIC RNA].
[2]	"Adaptation of reovirus to growth in the presence of protease inhibitor E64 segregates with a mutation in the carboxy terminus of viral outer-capsid protein sigma3." Ebert D.H., Wetzel J.D., Brumbaugh D.E., Chance S.R., Stobie L.E., Baer G.S., Dermody T.S. J. Virol. 75:3197-3206(2001) [PubMed] [Europe PMC] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [GENOMIC RNA]. Strain: Isolate D-EA1 and Isolate D-EA3.
[3]	"A plasmid-based reverse genetics system for animal double-stranded RNA viruses." Kobayashi T., Antar A.A., Boehme K.W., Danthi P., Eby E.A., Guglielmi K.M., Holm G.H., Johnson E.M., Maginnis M.S., Naik S., Skelton W.B., Wetzel J.D., Wilson G.J., Chappell J.D., Dermody T.S. Cell Host Microbe 1:147-157(2007) [PubMed] [Europe PMC] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [GENOMIC RNA]. Strain: Infectious clone.
[4]	"Double-stranded RNA-dependent protein kinase (PKR) is regulated by reovirus structural proteins." Yue Z., Shatkin A.J. Virology 234:364-371(1997) [PubMed] [Europe PMC] [Abstract] Cited for: FUNCTION.
[5]	"Structure of the reovirus outer capsid and dsRNA-binding protein sigma3 at 1.8 A resolution." Olland A.M., Jane-Valbuena J., Schiff L.A., Nibert M.L., Harrison S.C. EMBO J. 20:979-989(2001) [PubMed] [Europe PMC] [Abstract] Cited for: X-RAY CRYSTALLOGRAPHY (1.8 ANGSTROMS), ZINC-FINGER.

Cross-references

Sequence databases

EMBL
GenBank
DDBJ

K02739 Genomic RNA. Translation: AAA47283.1.
AF332137 Genomic RNA. Translation: AAK07648.1.
EF494444 Genomic RNA. Translation: ABP48922.1.

PIR

MNXRS3. A04127.

3D structure databases

PDBe
RCSB PDB
PDBj

Entry	Method	Resolution (Å)	Chain	Positions	PDBsum
1FN9	X-ray	1.80	A/B	1-365	[»]

ProteinModelPortal

P03527.

SMR

P03527. Positions 1-365.

ModBase

Search...

Protocols and materials databases

StructuralBiologyKnowledgebase

Search...

Family and domain databases

InterPro

IPR000153. Reo_capsid_sigma3.
IPR023634. Reovirus_capsid_sigma-3_dom.
[Graphical view]

Pfam

PF00979. Reovirus_cap. 1 hit.
[Graphical view]

SUPFAM

SSF64465. Reovirus_cap. 1 hit.

PROSITE

PS50158. ZF_CCHC. False negative.
[Graphical view]

ProtoNet

Search...

Other

EvolutionaryTrace

P03527.

Entry information

Entry name

SIGM3_REOVD

Accession

Primary (citable) accession number: P03527
Secondary accession number(s): A4ZY29, Q99AV2

Entry history

Integrated into UniProtKB/Swiss-Prot:	July 21, 1986
Last sequence update:	July 22, 2008
Last modified:	April 3, 2013
This is version 67 of the entry and version 2 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation program

Viral Protein Annotation Program