Reviewed, UniProtKB/Swiss-Prot P22601 (POLG_PVYC)

Names and origin

Protein names	Recommended name:     Genome polyprotein Cleaved into the following 3 chains:     1- Recommended name:             P1 proteinase         Alternative name(s):             N-terminal protein     2- Recommended name:             Helper component proteinase                 Short name=HC-pro               EC=3.4.22.45     3- Recommended name:             Protein P3
Organism	Potato virus Y (strain C) (PVY) (Potato virus C)
Taxonomic identifier	12217 [NCBI]
Taxonomic lineage	Viruses › ssRNA positive-strand viruses, no DNA stage › Potyviridae › Potyvirus
Virus host	Capsicum (peppers) [TaxID: 4071] Solanum lycopersicum (Tomato) (Lycopersicon esculentum) [TaxID: 4081] Nicotiana [TaxID: 4085] Solanum tuberosum (Potato) [TaxID: 4113]

Protein attributes

Sequence length	856 AA.
Sequence status	Fragment.
Sequence processing	The displayed sequence is further processed into a mature form.
Protein existence	Inferred from homology.

General annotation (Comments)

Function	HC is inactive with respect to its ability to effect aphid transmission of either PVC or PVY. Between the 2 amino acid changes which are specific to PVC-HC, the Lys to Glu-334 is more probably responsible of loss of binding to aphid stylet and thereby loss of aphid transmissibility. Displays proteolytic activity. Acts as a suppressor of RNA-mediated gene silencing, also known as post-transcriptional gene silencing (PTGS), a mechanism of plant viral defense that limits the accumulation of viral RNAs. May have RNA-binding activity By similarity.
Catalytic activity	Hydrolyzes a Gly-|-Gly bond at its own C-terminus, commonly in the sequence -Tyr-Xaa-Val-Gly-|-Gly, in the processing of the potyviral polyprotein.
Domain	The N-terminus of helper component proteinase is involved in interaction with stylets. The central part is involved in interaction with virions and the C-terminus is involved in cell-to cell movement of the virus.
Post-translational modification	The viral RNA of potyviruses is expressed as a single polyprotein which undergoes post-translational proteolytic processing by the main proteinase NIa-pro resulting in the production of at least ten individual proteins. The P1 proteinase and the HC-pro cleave only their respective C-termini autocatalytically By similarity.
Sequence similarities	Belongs to the potyviruses polyprotein family. Contains 1 peptidase C6 domain.

Ontologies

Keywords
Molecular function	Hydrolase Protease Suppressor of RNA silencing Thiol protease
Gene Ontology (GO)
Biological process	proteolysis Inferred from electronic annotation. Source: InterPro
Molecular function	cysteine-type endopeptidase 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 – 284	284	P1 proteinase Potential		PRO_0000040417
	Chain	285 – 740	456	Helper component proteinase Potential		PRO_0000040418
	Chain	741 – ›856	›116	Protein P3 By similarity		PRO_0000040419
Regions
	Motif	592 – 594	3	Involved in virions binding and aphid transmission By similarity
Sites
	Active site	192	1	For P1 proteinase activity By similarity
	Active site	201	1	For P1 proteinase activity Potential
	Active site	235	1	For P1 proteinase activity By similarity
	Active site	626	1	For helper component proteinase activity By similarity
	Active site	699	1	For helper component proteinase activity By similarity
	Site	284 – 285	2	Cleavage; by P1 proteinase Potential
	Site	740 – 741	2	Cleavage; by HC-pro Potential
Experimental info
	Non-terminal residue	856	1

Sequences

	Sequence		Length	Mass (Da)
	P22601-1 [UniParc]. Last modified August 1, 1991. Version 1. Checksum: 959EAE29BA0D60A8	FASTA	856	96,829
	10 20 30 40 50 60 MAIYMSTICF GSIECKLPYS PASCGHVTEE REVLASVEPF MDLEAQLSAR LLRQKHATVR 70 80 90 100 110 120 VLKNGTCAYR YKTDAQIVRI QKKLERKERD EYHFQMAAPS IVSKITIAGG DPPSKYEPQT 130 140 150 160 170 180 PKRVIHTTPR VRKVKKHSII KLTESQMNHL IKQVKRIMSA KKGSVHLINK KSTHVQYKEI 190 200 210 220 230 240 LGTTRAAVRT AHMMGLRRRV DFRCDMWTTE RLKCLARTDK WSNRVHTINI RKGDSGVILN 250 260 270 280 290 300 ADSLKGHFGR SSGGLFIVRG SHEGKLYDAR SKVTQGVLNS MVQFSNAENF WKGLDDNWAR 310 320 330 340 350 360 MRYPSDHTCI DGLPVEDCGR VAALMTHSIL PCYEITCPTC AQQYANLPAS DLFKLLHKHA 370 380 390 400 410 420 RDGLSRLGSD KDRFVHVNKF LVALEHLTEP VDLNLELFNE IFKSIGEKQQ APFKNLNVLN 430 440 450 460 470 480 NFFLKGKENT AHEWQVAQLS LLELARFQKN RTDNIKKGDI SFFRNKLSAK ANWNLYLSCD 490 500 510 520 530 540 NQLDKNANFL WGQREYHAKR FFSNFFEEVD PAKGYSAYEI RKHPNGTRKL SIGNLVVPLD 550 560 570 580 590 600 LAEFRQKMKG DYRKQPGVSK RCTSSKDGNY VYPCCCTTLD DGSAIESTFY PPTKKHLVIG 610 620 630 640 650 660 NSGDQKYVDL PKGDSEMLYI AKQGYCYINV FLAMLINVSE EDAKDFTKKV RDMCVPKLGT 670 680 690 700 710 720 WPTMMDLATT CAQMRIFYPD VHDAELPRIL VDHDTQTCHV VDSFGSQTTG YHILKASSVS 730 740 750 760 770 780 QLILFANDEL ESEIKHYRVG GVPNACPELG STISPFREGG VIMSESAALK LLLKGIFRPK 790 800 810 820 830 840 VMRQLLLDEP HLLILSILSP GILMAMYNNG IFELAVRLWI NEKQSIAMIA SLLSALALRV 850 SAAETLVAQR IIIDAA

References

[1]	"Comparative sequence of the helper component (HC) region of potato virus Y and a HC-defective strain, potato virus C." Thornbury D.W., Patterson C.A., Dessens J.T., Pirone T.P. Virology 178:573-578(1990) [PubMed: 2219708] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [GENOMIC RNA].
[2]	"Mutations in the potyvirus helper component protein: effects on interactions with virions and aphid stylets." Blanc S., Ammar E.D., Garcia-Lampasona S., Dolja V.V., Llave C., Baker J., Pirone T.P. J. Gen. Virol. 79:3119-3122(1998) [PubMed: 9880030] [Abstract] Cited for: FUNCTION OF HELPER COMPONENT PROTEINASE.
[3]	"Potyvirus proteins: a wealth of functions." Urcuqui-Inchima S., Haenni A.L., Bernardi F. Virus Res. 74:157-175(2001) [PubMed: 11226583] [Abstract] Cited for: REVIEW.

Cross-references

Sequence databases
EMBLGenBankDDBJ	M38377 Genomic RNA. Translation: AAA47183.1.
3D structure databases
ModBase	Search...
Family and domain databases
InterPro	IPR002540. Pept_S30_P1_potyvir. IPR001456. Peptidase_C6. [Graphical view]
Pfam	PF00851. Peptidase_C6. 1 hit. PF01577. Peptidase_S30. 1 hit. [Graphical view]
ProtoNet	Search...

Entry information

Entry name

POLG_PVYC

Accession

Primary (citable) accession number: P22601

Entry history

Integrated into UniProtKB/Swiss-Prot:	August 1, 1991
Last sequence update:	August 1, 1991
Last modified:	November 25, 2008
This is version 56 of the entry and version 1 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation project

Virus (Virus annotation project)