CFGA_TACTR
ID CFGA_TACTR Reviewed; 673 AA.
AC Q27082;
DT 17-JUN-2020, integrated into UniProtKB/Swiss-Prot.
DT 01-NOV-1996, sequence version 1.
DT 25-MAY-2022, entry version 80.
DE RecName: Full=Clotting factor G alpha subunit {ECO:0000303|PubMed:8288603};
DE EC=3.2.1.- {ECO:0000305};
DE Flags: Precursor;
OS Tachypleus tridentatus (Japanese horseshoe crab).
OC Eukaryota; Metazoa; Ecdysozoa; Arthropoda; Chelicerata; Merostomata;
OC Xiphosura; Limulidae; Tachypleus.
OX NCBI_TaxID=6853 {ECO:0000312|EMBL:BAA04044.1};
RN [1] {ECO:0000312|EMBL:BAA04044.1}
RP NUCLEOTIDE SEQUENCE [MRNA], PROTEIN SEQUENCE OF 20-28; 78-103; 108-133;
RP 212-236; 366-373; 424-436; 440-467; 412-427 AND 581-588, AND TISSUE
RP SPECIFICITY.
RX PubMed=8288603; DOI=10.1016/s0021-9258(17)42267-8;
RA Seki N., Muta T., Oda T., Iwaki D., Kuma K., Miyata T., Iwanaga S.;
RT "Horseshoe crab (1,3)-beta-D-glucan-sensitive coagulation factor G. A
RT serine protease zymogen heterodimer with similarities to beta-glucan-
RT binding proteins.";
RL J. Biol. Chem. 269:1370-1374(1994).
RN [2] {ECO:0000305}
RP FUNCTION, SUBUNIT, TISSUE SPECIFICITY, BIOTECHNOLOGY, AND PROTEOLYTIC
RP CLEAVAGE.
RX PubMed=7822328; DOI=10.1074/jbc.270.2.892;
RA Muta T., Seki N., Takaki Y., Hashimoto R., Oda T., Iwanaga A., Tokunaga F.,
RA Iwanaga S.;
RT "Purified horseshoe crab factor G. Reconstitution and characterization of
RT the (1-->3)-beta-D-glucan-sensitive serine protease cascade.";
RL J. Biol. Chem. 270:892-897(1995).
CC -!- FUNCTION: Component of the heterodimer clotting factor G which may play
CC a role in defense mechanisms against fungi (Probable). Initiates a
CC (1->3)-beta-glucan-sensing clotting pathway whereby the alpha subunit
CC binds to glucans containing (1->3)-beta linkages, which are components
CC of the fungal cell wall, and the beta subunit catalyzes the activation
CC of proclotting enzyme (PubMed:7822328). {ECO:0000269|PubMed:7822328,
CC ECO:0000305|PubMed:7822328}.
CC -!- SUBUNIT: Clotting factor G is a heterodimer composed of two non-
CC covalently associated subunits, alpha and beta.
CC {ECO:0000269|PubMed:7822328}.
CC -!- TISSUE SPECIFICITY: Expressed in hemocytes (at protein level).
CC {ECO:0000269|PubMed:7822328, ECO:0000269|PubMed:8288603}.
CC -!- PTM: In presence of (1->3)-beta-glucan, proteolytically cleaved into a
CC 55kDa and a 17kDa forms. {ECO:0000269|PubMed:7822328}.
CC -!- BIOTECHNOLOGY: Clotting factor G is a component of the Limulus test
CC used to detect bacterial endotoxins in fluids.
CC {ECO:0000305|PubMed:7822328}.
CC -!- SIMILARITY: Belongs to the glycosyl hydrolase 16 family.
CC {ECO:0000255|PROSITE-ProRule:PRU01098}.
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DR EMBL; D16622; BAA04044.1; -; mRNA.
DR PIR; A49878; A49878.
DR AlphaFoldDB; Q27082; -.
DR SMR; Q27082; -.
DR CAZy; CBM13; Carbohydrate-Binding Module Family 13.
DR CAZy; CBM6; Carbohydrate-Binding Module Family 6.
DR CAZy; GH16; Glycoside Hydrolase Family 16.
DR MEROPS; X14.001; -.
DR GO; GO:1905370; C:serine-type endopeptidase complex; IDA:UniProtKB.
DR GO; GO:0030246; F:carbohydrate binding; IEA:UniProtKB-KW.
DR GO; GO:0004553; F:hydrolase activity, hydrolyzing O-glycosyl compounds; IEA:InterPro.
DR GO; GO:0005975; P:carbohydrate metabolic process; IEA:InterPro.
DR GO; GO:0042381; P:hemolymph coagulation; IDA:UniProtKB.
DR CDD; cd00161; RICIN; 1.
DR InterPro; IPR006584; Cellulose-bd_IV.
DR InterPro; IPR005084; CMB_fam6.
DR InterPro; IPR013320; ConA-like_dom_sf.
DR InterPro; IPR008979; Galactose-bd-like_sf.
DR InterPro; IPR000757; GH16.
DR InterPro; IPR035992; Ricin_B-like_lectins.
DR InterPro; IPR000772; Ricin_B_lectin.
DR Pfam; PF03422; CBM_6; 2.
DR Pfam; PF00722; Glyco_hydro_16; 1.
DR Pfam; PF14200; RicinB_lectin_2; 2.
DR SMART; SM00606; CBD_IV; 2.
DR SMART; SM00458; RICIN; 1.
DR SUPFAM; SSF49785; SSF49785; 2.
DR SUPFAM; SSF49899; SSF49899; 1.
DR SUPFAM; SSF50370; SSF50370; 1.
DR PROSITE; PS51175; CBM6; 2.
DR PROSITE; PS51762; GH16_2; 1.
DR PROSITE; PS50231; RICIN_B_LECTIN; 1.
PE 1: Evidence at protein level;
KW Direct protein sequencing; Glycoprotein; Glycosidase; Hemolymph clotting;
KW Hydrolase; Lectin; Repeat; Signal.
FT SIGNAL 1..19
FT /evidence="ECO:0000269|PubMed:8288603"
FT CHAIN 20..673
FT /note="Clotting factor G alpha subunit"
FT /evidence="ECO:0000255"
FT /id="PRO_5013107839"
FT DOMAIN 27..257
FT /note="GH16"
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU01098"
FT DOMAIN 266..404
FT /note="Ricin B-type lectin"
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU00174"
FT DOMAIN 411..533
FT /note="CBM6 1"
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU00523"
FT DOMAIN 549..671
FT /note="CBM6 2"
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU00523"
FT ACT_SITE 137
FT /note="Nucleophile"
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU01098"
FT ACT_SITE 142
FT /note="Proton donor"
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU01098"
FT SITE 169..170
FT /note="Cleavage"
FT /evidence="ECO:0000305|PubMed:8288603"
FT CARBOHYD 186
FT /note="N-linked (GlcNAc...) asparagine"
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU00498"
SQ SEQUENCE 673 AA; 75952 MW; B6CD46C3480D2333 CRC64;
MLVLLCCVVL HVGVARICCS HEPKWQLVWS DEFTNGISSD WEFEMGNGLN GWGNNELQYY
RRENAQVEGG KLVITAKRED YDGFKYTSAR LKTQFDKSWK YGKIEAKMAI PSFRGVWVMF
WMSGDNTNYV RWPSSGEIDF IEHRNTNNEK VRGTIHWSTP DGAHAHHNRE SNTNGIDYHI
YSVEWNSSIV KWFVNGNQYF EVKIQGGVNG KSAFRNKVFV ILNMAIGGNW PGFDVADEAF
PAKMYIDYVR VYQDASTSSP VGDTSLDGYY FVQNRHSELY LDVTDASNED GAFLQQWSYS
GNENQQFDFE HLENNVYKIT NKKSGKSLDV YNFGTENGVR IQQWSYGGAR NQQFTVQSVG
DGYYKIIPRG SGKLVEVADF SKDAGGKIQQ WSDNNQLSGQ WKLIKSKSYS KLIQAESYFD
SSKVQLEDTS DVGGGKNVKC DNEGAWMAYK DIDFPSSGNY RIEYRVASER AGGKLSLDLN
AGSIVLGMLD VPSTGGWQKW TTISHTVNVD SGTYNLGIYV QRASWNINWI KITKIPEQSN
LNQGRRNSKL IQAESYFSYS EVQLEDTLDV GGGKNVKCDK EGAWMAYKDI DFPSSGSYRV
EYRVASERAG GKLSLDLNAG SIVLGMLDIP STGGLQKWTT ISHIVNVDLG TYNLGIYVQK
ASWNINWIRI TKV
