P21902 (PCE_TACTR) Reviewed, UniProtKB/Swiss-Prot

Names and origin

Protein names	Recommended name: Proclotting enzyme EC=3.4.21.86 Cleaved into the following 2 chains: Proclotting enzyme light chain Proclotting enzyme heavy chain
Organism	Tachypleus tridentatus (Japanese horseshoe crab)
Taxonomic identifier	6853 [NCBI]
Taxonomic lineage	Eukaryota › Metazoa › Arthropoda › Chelicerata › Merostomata › Xiphosura › Limulidae › Tachypleus

Protein attributes

Sequence length	375 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	This enzyme is closely associated with an endotoxin-sensitive hemolymph coagulation system in limulus. Its active form catalyzes the conversion of coagulogen to insoluble coagulin gel.
Catalytic activity	Selective cleavage of 18-Arg-|- and 47-Arg-|- bonds in coagulogen to form coagulin and fragments.
Subunit structure	Upon activation by factor B, it is converted to a two-chain active form composed of a light and a heavy chain.
Subcellular location	Secreted. Note: Secreted in hemolymph.
Post-translational modification	Contains six O-linked carbohydrate chains in the N-terminal light chain generated after activation.
Sequence similarities	Belongs to the peptidase S1 family. Contains 1 peptidase S1 domain.

Ontologies

Keywords
Biological process	Hemolymph clotting
Cellular component	Secreted
Domain	Signal
Molecular function	Hydrolase Protease Serine protease
PTM	Cleavage on pair of basic residues Disulfide bond Glycoprotein Pyrrolidone carboxylic acid Zymogen
Technical term	Direct protein sequencing
Gene Ontology (GO)
Biological process	hemolymph coagulation Inferred from electronic annotation. Source: UniProtKB-KW proteolysis Inferred from electronic annotation. Source: UniProtKB-KW
Cellular component	extracellular region Inferred from electronic annotation. Source: UniProtKB-SubCell
Molecular function	serine-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 – 17	17	Or 25 Potential
	Propeptide	18 – 29	12	Potential		PRO_0000028427
	Chain	30 – 127	98	Proclotting enzyme light chain		PRO_0000028428
	Chain	128 – 375	248	Proclotting enzyme heavy chain		PRO_0000028429
Regions
	Domain	128 – 375	248	Peptidase S1
Sites
	Active site	172	1	Charge relay system By similarity
	Active site	228	1	Charge relay system By similarity
	Active site	326	1	Charge relay system By similarity
Amino acid modifications
	Modified residue	30	1	Pyrrolidone carboxylic acid
	Glycosylation	122	1	N-linked (GlcNAc...)
	Glycosylation	235	1	N-linked (GlcNAc...)
	Glycosylation	304	1	N-linked (GlcNAc...)
	Disulfide bond	40 ↔ 83		Ref.1
	Disulfide bond	50 ↔ 73		Ref.1
	Disulfide bond	56 ↔ 84		Ref.1
	Disulfide bond	118 ↔ 248		Interchain (between light and heavy chains) Ref.1
	Disulfide bond	157 ↔ 173		Ref.1
	Disulfide bond	295 ↔ 311		Ref.1
	Disulfide bond	322 ↔ 351		Ref.1

Sequences

	Sequence		Length	Mass (Da)
	P21902 [UniParc]. Last modified May 1, 1991. Version 1. Checksum: 94209E514DFCF8FB	FASTA	375	41,592
	10 20 30 40 50 60 MLVNNVFSLL CFPLLMSVVR CSTLSRQRRQ FVFPDEEELC SNRFTEEGTC KNVLDCRILL 70 80 90 100 110 120 QKNDYNLLKE SICGFEGITP KVCCPKSSHV ISSTQAPPET TTTERPPKQI PPNLPEVCGI 130 140 150 160 170 180 HNTTTTRIIG GREAPIGAWP WMTAVYIKQG GIRSVQCGGA LVTNRHVITA SHCVVNSAGT 190 200 210 220 230 240 DVMPADVFSV RLGEHNLYST DDDSNPIDFA VTSVKHHEHF VLATYLNDIA ILTLNDTVTF 250 260 270 280 290 300 TDRIRPICLP YRKLRYDDLA MRKPFITGWG TTAFNGPSSA VLREVQLPIW EHEACRQAYE 310 320 330 340 350 360 KDLNITNVYM CAGFADGGKD ACQGDSGGPM MLPVKTGEFY LIGIVSFGKK CALPGFPGVY 370 TKVTEFLDWI AEHMV

References

[1]	"Proclotting enzyme from horseshoe crab hemocytes. cDNA cloning, disulfide locations, and subcellular localization." Muta T., Hashimoto R., Miyata T., Nishimura H., Toh Y., Iwanaga S. J. Biol. Chem. 265:22426-22433(1990) [PubMed: 2266134] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [MRNA], PARTIAL PROTEIN SEQUENCE, DISULFIDE BONDS. Tissue: Hemocyte.
+	Additional computationally mapped references.

Cross-references

Sequence databases
EMBL GenBank DDBJ	M58366 mRNA. Translation: AAA30094.1.
PIR	A23689.
3D structure databases
ProteinModelPortal	P21902.
ModBase	Search...
Protein family/group databases
MEROPS	S01.221.
Protocols and materials databases
StructuralBiologyKnowledgebase	Search...
Family and domain databases
InterPro	IPR022700. CLIP. IPR006604. Disulphide_knot_CLIP. IPR009003. Pept_cys/ser_Trypsin-like. IPR018114. Peptidase_S1/S6_AS. IPR001254. Peptidase_S1_S6. IPR001314. Peptidase_S1A. [Graphical view]
Pfam	PF12032. CLIP. 1 hit. PF00089. Trypsin. 1 hit. [Graphical view]
PRINTS	PR00722. CHYMOTRYPSIN.
SMART	SM00680. CLIP. 1 hit. SM00020. Tryp_SPc. 1 hit. [Graphical view]
SUPFAM	SSF50494. Pept_Ser_Cys. 1 hit.
PROSITE	PS50240. TRYPSIN_DOM. 1 hit. PS00134. TRYPSIN_HIS. 1 hit. PS00135. TRYPSIN_SER. 1 hit. [Graphical view]
ProtoNet	Search...
Other
PMAP-CutDB	P21902.

Entry information

Entry name

PCE_TACTR

Accession

Primary (citable) accession number: P21902

Entry history

Integrated into UniProtKB/Swiss-Prot:	May 1, 1991
Last sequence update:	May 1, 1991
Last modified:	November 16, 2011
This is version 78 of the entry and version 1 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)