Reviewed, UniProtKB/Swiss-Prot P05994 (PAPA4_CARPA)

Names and origin

Protein names	Recommended name:     Papaya proteinase 4     EC=3.4.22.25 Alternative name(s):     Papaya proteinase IV       Short name=PPIV     Papaya peptidase B     Glycyl endopeptidase
Organism	Carica papaya (Papaya)
Taxonomic identifier	3649 [NCBI]
Taxonomic lineage	Eukaryota › Viridiplantae › Streptophyta › Embryophyta › Tracheophyta › Spermatophyta › Magnoliophyta › eudicotyledons › core eudicotyledons › rosids › eurosids II › Brassicales › Caricaceae › Carica

Protein attributes

Sequence length	348 AA.
Sequence status	Complete.
Sequence processing	The displayed sequence is further processed into a mature form.
Protein existence	Evidence at protein level.

General annotation (Comments)

Function	Thiol protease with a substrate specificity very different from the other thiol proteases.
Catalytic activity	Preferential cleavage: Gly-|-Xaa, in proteins and in small molecule substrates.
Enzyme regulation	Not inhibited by cystatin.
Miscellaneous	Substitution of the conserved Gly residue by Glu-155 could possibly explain the unusual specificity.
Sequence similarities	Belongs to the peptidase C1 family.

Ontologies

Keywords
Domain	Signal
Molecular function	Hydrolase Protease Thiol protease
PTM	Disulfide bond Zymogen
Technical term	3D-structure Direct protein sequencing
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

Signal peptide

1 – 18

18

Potential

Propeptide

19 – 132

114

Activation peptide Ref.2 Ref.3

PRO_0000026412

Chain

133 – 348

216

Papaya proteinase 4

PRO_0000026413

Sites

Active site

157

1

By similarity

Active site

291

1

By similarity

Active site

311

1

By similarity

Amino acid modifications

Disulfide bond

154 ↔ 195

Disulfide bond

188 ↔ 227

Disulfide bond

285 ↔ 336

Experimental info

Sequence conflict

190

1

K → L AA sequence Ref.2

Secondary structure

1

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348

Helix Strand Turn

Details...

Turn

139 – 143

5

Beta strand

153 – 155

3

Helix

157 – 174

18

Helix

182 – 188

7

Beta strand

190 – 192

3

Helix

200 – 210

11

Turn

215 – 217

3

Helix

229 – 232

4

Beta strand

241 – 244

4

Helix

250 – 257

8

Beta strand

262 – 266

5

Helix

271 – 274

4

Beta strand

278 – 281

4

Beta strand

291 – 301

11

Beta strand

304 – 310

7

Beta strand

322 – 326

5

Helix

335 – 337

3

Beta strand

343 – 346

4

Sequences

	Sequence		Length	Mass (Da)
	P05994-1 [UniParc]. Last modified October 1, 1996. Version 3. Checksum: 40855EDD37F68A8E	FASTA	348	39,024
	10 20 30 40 50 60 MAIICSFSKL LFVAICLFGH MSLSYCDFSI VGYSQDDLTS TERLIQLFNS WMLKHNKNYK 70 80 90 100 110 120 NVDEKLYRFE IFKDNLKYID ERNKMINGYW LGLNEFSDLS NDEFKEKYVG SLPEDYTNQP 130 140 150 160 170 180 YDEEFVNEDI VDLPESVDWR AKGAVTPVKH QGYCESCWAF STVATVEGIN KIKTGNLVEL 190 200 210 220 230 240 SEQELVDCDK QSYGCNRGYQ STSLQYVAQN GIHLRAKYPY IAKQQTCRAN QVGGPKVKTN 250 260 270 280 290 300 GVGRVQSNNE GSLLNAIAHQ PVSVVVESAG RDFQNYKGGI FEGSCGTKVD HAVTAVGYGK 310 320 330 340 SGGKGYILIK NSWGPGWGEN GYIRIRRASG NSPGVCGVYR SSYYPIKN

References

[1]	"Recombinant pro-regions from papain and papaya proteinase IV-are selective high affinity inhibitors of the mature papaya enzymes." Taylor M.A., Baker K.C., Briggs G.S., Connerton I.F., Cummings N.J., Pratt K.A., Revell D.F., Freedman R.B., Goodenough P.W. Protein Eng. 8:59-62(1995) [PubMed: 7770454] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [MRNA]. Tissue: Leaf.
[2]	"Papaya proteinase IV amino acid sequence." Ritonja A., Buttle D.J., Rawlings N.D., Turk V., Barrett A.J. FEBS Lett. 258:109-112(1989) [PubMed: 2591528] [Abstract] Cited for: PROTEIN SEQUENCE OF 133-348.
[3]	"N-terminal homology in three cysteinyl proteases from Papaya latex." Lynn K.R., Yaguchi M. Biochim. Biophys. Acta 581:363-364(1979) [PubMed: 518921] [Abstract] Cited for: PROTEIN SEQUENCE OF 133-150.
[4]	"Molecular cloning of two cysteine proteinases from paw-paw (Carica papaya)." McKee R.A., Adams S., Matthews J.A., Smith C.J., Smith H. Biochem. J. 237:105-110(1986) [PubMed: 3541893] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [MRNA] OF 287-348.
[5]	"Selective cleavage of glycyl bonds by papaya proteinase IV." Buttle D.J., Ritonja A., Pearl L.H., Turk V., Barrett A.J. FEBS Lett. 260:195-197(1990) [PubMed: 2404797] [Abstract] Cited for: SUBSTRATE SPECIFICITY.
[6]	"Crystal structure of glycyl endopeptidase from Carica papaya: a cysteine endopeptidase of unusual substrate specificity." O'Hara B.P., Hemmings A.M., Buttle D.J., Pearl L.H. Biochemistry 34:13190-13195(1995) [PubMed: 7548082] [Abstract] Cited for: X-RAY CRYSTALLOGRAPHY (2.1 ANGSTROMS).

Cross-references

Sequence databases

EMBLGenBankDDBJ

X78056 mRNA. Translation: CAA54974.1.
X03970 mRNA. Translation: CAA27608.1.

PIR

S06837.
T09798.

3D structure databases

PDBPDBe

Entry	Method	Resolution (Å)	Chain	Positions	PDBsum
1GEC	X-ray	2.10	E	133-348	[»]

SMR

P05994. Positions 38-348.

ModBase

Search...

Protein family/group databases

MEROPS

C01.004.

Enzyme and pathway databases

BRENDA

3.4.22.25. 18730.

Family and domain databases

InterPro

IPR000169. Pept_cys_AS.
IPR013128. Peptidase_C1A.
IPR000668. Peptidase_C1A_C.
IPR013201. Prot_inhib_I29.
[Graphical view]

PANTHER

PTHR12411. Peptidase_C1A. 1 hit.

Pfam

PF08246. Inhibitor_I29. 1 hit.
PF00112. Peptidase_C1. 1 hit.
[Graphical view]

PRINTS

PR00705. PAPAIN.

ProDom

PD000158. Peptidase_C1. 1 hit.
[Graphical view] [Entries sharing at least one domain]

SMART

SM00645. Pept_C1. 1 hit.
[Graphical view]

PROSITE

PS00640. THIOL_PROTEASE_ASN. 1 hit.
PS00139. THIOL_PROTEASE_CYS. 1 hit.
PS00639. THIOL_PROTEASE_HIS. 1 hit.
[Graphical view]

ProtoNet

Search...

Entry information

Entry name

PAPA4_CARPA

Accession

Primary (citable) accession number: P05994

Entry history

Integrated into UniProtKB/Swiss-Prot:	November 1, 1988
Last sequence update:	October 1, 1996
Last modified:	June 16, 2009
This is version 83 of the entry and version 3 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation project

PPAP (Plant Proteome Annotation Project)