ID   CO3_LETCA               Reviewed;        1673 AA.
AC   Q00685;
DT   01-FEB-1996, integrated into UniProtKB/Swiss-Prot.
DT   01-FEB-1996, sequence version 1.
DT   03-AUG-2022, entry version 103.
DE   RecName: Full=Complement C3;
DE   Contains:
DE     RecName: Full=Complement C3 beta chain;
DE   Contains:
DE     RecName: Full=Complement C3 alpha chain;
DE   Contains:
DE     RecName: Full=C3a anaphylatoxin;
DE   Contains:
DE     RecName: Full=Complement C3 gamma chain;
DE   Flags: Precursor; Fragment;
GN   Name=C3;
OS   Lethenteron camtschaticum (Japanese lamprey) (Lampetra japonica).
OC   Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Cyclostomata;
OC   Hyperoartia; Petromyzontiformes; Petromyzontidae; Lethenteron.
OX   NCBI_TaxID=980415;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [MRNA].
RC   TISSUE=Liver;
RX   PubMed=1578150;
RA   Nonaka M., Takahashi M.;
RT   "Complete complementary DNA sequence of the third component of complement
RT   of lamprey. Implication for the evolution of thioester containing
RT   proteins.";
RL   J. Immunol. 148:3290-3295(1992).
CC   -!- FUNCTION: C3 plays a central role in the activation of the complement
CC       system. After activation (C3b), it can bind covalently, via its
CC       reactive thioester, to cell surface carbohydrates or immune aggregates.
CC       Cyclostomates C3 appears to represent the common ancestor of mammalian
CC       C3 and C4, showing similarities to both proteins.
CC   -!- SUBCELLULAR LOCATION: Secreted.
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DR   EMBL; D10087; BAA00983.1; -; mRNA.
DR   PIR; I50806; I50806.
DR   AlphaFoldDB; Q00685; -.
DR   SMR; Q00685; -.
DR   MEROPS; I39.951; -.
DR   PRIDE; Q00685; -.
DR   GO; GO:0005615; C:extracellular space; IEA:InterPro.
DR   GO; GO:0004866; F:endopeptidase inhibitor activity; IEA:InterPro.
DR   GO; GO:0006958; P:complement activation, classical pathway; IEA:UniProtKB-KW.
DR   GO; GO:0006954; P:inflammatory response; IEA:UniProtKB-KW.
DR   GO; GO:0045087; P:innate immune response; IEA:UniProtKB-KW.
DR   CDD; cd00017; ANATO; 1.
DR   Gene3D; 2.40.50.120; -; 1.
DR   Gene3D; 2.60.40.10; -; 2.
DR   Gene3D; 2.60.40.690; -; 1.
DR   InterPro; IPR009048; A-macroglobulin_rcpt-bd.
DR   InterPro; IPR036595; A-macroglobulin_rcpt-bd_sf.
DR   InterPro; IPR011625; A2M_N_BRD.
DR   InterPro; IPR011626; Alpha-macroglobulin_TED.
DR   InterPro; IPR000020; Anaphylatoxin/fibulin.
DR   InterPro; IPR018081; Anaphylatoxin_comp_syst.
DR   InterPro; IPR041425; C3/4/5_MG1.
DR   InterPro; IPR035711; Complement_C3-like.
DR   InterPro; IPR013783; Ig-like_fold.
DR   InterPro; IPR008964; Invasin/intimin_cell_adhesion.
DR   InterPro; IPR001599; Macroglobln_a2.
DR   InterPro; IPR019742; MacrogloblnA2_CS.
DR   InterPro; IPR002890; MG2.
DR   InterPro; IPR041555; MG3.
DR   InterPro; IPR040839; MG4.
DR   InterPro; IPR001134; Netrin_domain.
DR   InterPro; IPR018933; Netrin_module_non-TIMP.
DR   InterPro; IPR008930; Terpenoid_cyclase/PrenylTrfase.
DR   InterPro; IPR008993; TIMP-like_OB-fold.
DR   PANTHER; PTHR11412:SF81; PTHR11412:SF81; 1.
DR   Pfam; PF00207; A2M; 1.
DR   Pfam; PF07703; A2M_BRD; 1.
DR   Pfam; PF07677; A2M_recep; 1.
DR   Pfam; PF01821; ANATO; 1.
DR   Pfam; PF17790; MG1; 1.
DR   Pfam; PF01835; MG2; 1.
DR   Pfam; PF17791; MG3; 1.
DR   Pfam; PF17789; MG4; 1.
DR   Pfam; PF01759; NTR; 1.
DR   Pfam; PF07678; TED_complement; 1.
DR   SMART; SM01360; A2M; 1.
DR   SMART; SM01359; A2M_N_2; 1.
DR   SMART; SM01361; A2M_recep; 1.
DR   SMART; SM00104; ANATO; 1.
DR   SMART; SM00643; C345C; 1.
DR   SUPFAM; SSF47686; SSF47686; 1.
DR   SUPFAM; SSF48239; SSF48239; 1.
DR   SUPFAM; SSF49373; SSF49373; 1.
DR   SUPFAM; SSF49410; SSF49410; 1.
DR   SUPFAM; SSF50242; SSF50242; 1.
DR   PROSITE; PS00477; ALPHA_2_MACROGLOBULIN; 1.
DR   PROSITE; PS01177; ANAPHYLATOXIN_1; 1.
DR   PROSITE; PS01178; ANAPHYLATOXIN_2; 1.
DR   PROSITE; PS50189; NTR; 1.
PE   2: Evidence at transcript level;
KW   Cleavage on pair of basic residues; Complement pathway; Disulfide bond;
KW   Glycoprotein; Immunity; Inflammatory response; Innate immunity; Secreted;
KW   Signal; Thioester bond.
FT   SIGNAL          <1..13
FT                   /evidence="ECO:0000255"
FT   CHAIN           14..1673
FT                   /note="Complement C3"
FT                   /id="PRO_0000005947"
FT   CHAIN           14..653
FT                   /note="Complement C3 beta chain"
FT                   /evidence="ECO:0000250"
FT                   /id="PRO_0000005948"
FT   CHAIN           657..1375
FT                   /note="Complement C3 alpha chain"
FT                   /evidence="ECO:0000250"
FT                   /id="PRO_0000005949"
FT   CHAIN           657..732
FT                   /note="C3a anaphylatoxin"
FT                   /evidence="ECO:0000250"
FT                   /id="PRO_0000005950"
FT   CHAIN           1379..1673
FT                   /note="Complement C3 gamma chain"
FT                   /evidence="ECO:0000250"
FT                   /id="PRO_0000005951"
FT   DOMAIN          678..713
FT                   /note="Anaphylatoxin-like"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00022"
FT   DOMAIN          1525..1671
FT                   /note="NTR"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00295"
FT   CARBOHYD        217
FT                   /note="N-linked (GlcNAc...) asparagine"
FT                   /evidence="ECO:0000255"
FT   CARBOHYD        639
FT                   /note="N-linked (GlcNAc...) asparagine"
FT                   /evidence="ECO:0000255"
FT   CARBOHYD        1190
FT                   /note="N-linked (GlcNAc...) asparagine"
FT                   /evidence="ECO:0000255"
FT   CARBOHYD        1317
FT                   /note="N-linked (GlcNAc...) asparagine"
FT                   /evidence="ECO:0000255"
FT   CARBOHYD        1560
FT                   /note="N-linked (GlcNAc...) asparagine"
FT                   /evidence="ECO:0000255"
FT   DISULFID        678..705
FT                   /evidence="ECO:0000250"
FT   DISULFID        679..712
FT                   /evidence="ECO:0000250"
FT   DISULFID        692..713
FT                   /evidence="ECO:0000250"
FT   DISULFID        1525..1600
FT                   /evidence="ECO:0000250"
FT   DISULFID        1546..1671
FT                   /evidence="ECO:0000250"
FT   CROSSLNK        986..989
FT                   /note="Isoglutamyl cysteine thioester (Cys-Gln)"
FT                   /evidence="ECO:0000250"
FT   NON_TER         1
SQ   SEQUENCE   1673 AA;  187768 MW;  4B5FC756B123A506 CRC64;
     VLLLMSVGTS VTQDPMVLLS VPSVILIGSD VNVLVDHAAS TEDVSVVVRA EEFLTKKQLA
     TQTITLTQLD PAIATLKLGF DIENPDKTNS ASTKHHVRLV AKVESKSFNK EITAHALLSY
     RSGHVVVQTD KPIYTPDEKV KYRMFPMNRE DVHRIPVRQS MTVDIVNADG VIVERQIKTI
     KATDEGIVDG TSFTIPAISK HGTWKIFARM SGAPNINSSA EFDVREYILP TFEVKINPKQ
     RVFHINDEEF VVDITANYFN QELVSGTAYV RYFLENGDVP KLVDSSSTTL VAGEGLSILK
     KEKLLKLFPN AKDLLAFSLT IKTTVLSSQA AETEEAELVG IKIVESRYQI TATKTSRYFK
     PELPYFIQVE VRNADGSPSK EVDVVAKVQV GSATINPQKM RTDSNGLTSF TVTPPNVNQL
     TVTVRTDERH PSNEQGELVY TAQKYASASY MHIDVTRIMR LGETLNVFLT AKTTQLNAVT
     HFTYMVLTRG VIVKTNRKTK ESGGGPSNVR IPITPDMAPR FRFLAYYILP GGEIVADSVT
     VEVTELCKSQ VSLSLKGRPT LEPKAMLTLD LIGEPDARVG LLAVDQAVYA VNRKHRLTQD
     RVWKAMETFD TGCTAEGGAG RPGVFSDAGL ALITSKGLNT TDRSEIGCPK VPSRKPRQLS
     MLQIRREAEK YTQEFRKCCV DGLKMSPTGQ GCEERLKRVT GPKECVDAFL QCCKKAEEYR
     KSESLGAKTV LRRNDFMELD LMNEDEVNMM AYFPQSWGWN KYKNSCKYGR HPQIRLQLPD
     TITTWNMQAV SISKTRGVCL ADPLLLVSTK DFFIKLHLPY SVKRGEQTEI RVILYNYMEE
     SLTILTEMDI VESICSTSKS GAKPSQKSTV KGKGAMVVSF PIVPLKIGEH HISIRSRVYG
     RTFGDGVQKI LRVAPEGVRD IRSESRSVHV EERETFFIKN EISPDVVPNS DVLTFISVKG
     DELAETMVNC LDAKSISNLI QIPTGCGEQN MIKMAPTTLT LIYLDSVQEW EKIGLHRREE
     AIGFLKQGYS RELSYRKADH SYAAFIKRPS STWLTAFVVK VYSLAKRVII VDNQELCGPV
     EWIIKNRQNS DGSYREDGPV IHREMQGGVG GTEGHVSMTA FILIGIQQAQ EYCGVSVPNY
     KQSMNRAVQF LASKVSDLKR MYTIAITRYA LALQDPESEA AHSSWKKLEN RTTFESKGHR
     YWKAEETSHV LRMSAISVEA TAYGLLTYLR KKDYESAREI VDWLTEQRNY GGGFQSTQDT
     ILALQAMAQY KMDSSSKELI DVQLEITSPK NNFEKKMKIT EETRFVQEPH KIPPGGNITI
     KASGRGTFTL SIMSVFNKVA PSSKSCSTFD LKVTMTEADD GESPQGRLGW FDGKRRRRRD
     IGDEGGVEAV YRMNMCTRYK PRKEDLSSES GMTIIEVNML TGFIPDKNDL IQLKESVDKY
     ISNYEITDSV LIIYWDKVPS TEDYCFAFKI KQMLRSDMIQ PVTASVYDYY SPADKCTRLY
     NLPGGYVELS PLCQNDLCQC VEVSCPAKKP KFDTSITVLH RQEAACVAGI DYAYVGIVDN
     RTEVGSFVYY TVNIQTVIKS GQDQAIQPKA TRLFIVTRSC DGRLGMETPR QYLLMGRKGE
     TKDRNDRFQY VLDASSWVEQ WPVDEKCNQP NVQTFCAIKR EYEFSMQIQG CSS