ID   SPRM_HALRO              Reviewed;         388 AA.
AC   Q966V2;
DT   13-JUL-2010, integrated into UniProtKB/Swiss-Prot.
DT   01-DEC-2001, sequence version 1.
DT   03-AUG-2022, entry version 78.
DE   RecName: Full=Spermosin {ECO:0000303|PubMed:11856325, ECO:0000312|EMBL:BAB60896.1};
DE            EC=3.4.21.99;
DE   Contains:
DE     RecName: Full=Spermosin L1 light chain {ECO:0000303|PubMed:11856325};
DE   Contains:
DE     RecName: Full=Spermosin L2 light chain {ECO:0000303|PubMed:11856325};
DE   Contains:
DE     RecName: Full=Spermosin heavy chain {ECO:0000303|PubMed:11856325};
DE   Flags: Precursor;
OS   Halocynthia roretzi (Sea squirt) (Cynthia roretzi).
OC   Eukaryota; Metazoa; Chordata; Tunicata; Ascidiacea; Stolidobranchia;
OC   Pyuridae; Halocynthia.
OX   NCBI_TaxID=7729;
RN   [1] {ECO:0000305, ECO:0000312|EMBL:BAB60896.1}
RP   NUCLEOTIDE SEQUENCE [MRNA], PROTEIN SEQUENCE OF 23-26; 97-100 AND 130-163,
RP   SUBUNIT, AND TISSUE SPECIFICITY.
RC   TISSUE=Gonad {ECO:0000269|PubMed:11856325}, and
RC   Sperm {ECO:0000269|PubMed:11856325};
RX   PubMed=11856325; DOI=10.1046/j.0014-2956.2001.02696.x;
RA   Kodama E., Baba T., Kohno N., Satoh S., Yokosawa H., Sawada H.;
RT   "Spermosin, a trypsin-like protease from ascidian sperm: cDNA cloning,
RT   protein structures and functional analysis.";
RL   Eur. J. Biochem. 269:657-663(2002).
RN   [2] {ECO:0000305}
RP   ACTIVITY REGULATION.
RX   PubMed=6381175; DOI=10.1016/0012-1606(84)90281-1;
RA   Sawada H., Yokosawa H., Someno T., Saino T., Ishii S.;
RT   "Evidence for the participation of two sperm proteases, spermosin and
RT   acrosin, in fertilization of the ascidian, Halocynthia roretzi: inhibitory
RT   effects of leupeptin analogs on enzyme activities and fertilization.";
RL   Dev. Biol. 105:246-249(1984).
RN   [3] {ECO:0000305}
RP   FUNCTION, CATALYTIC ACTIVITY, ACTIVITY REGULATION, AND BIOPHYSICOCHEMICAL
RP   PROPERTIES.
RX   PubMed=6365918; DOI=10.1016/s0021-9258(17)43233-9;
RA   Sawada H., Yokosawa H., Ishii S.;
RT   "Purification and characterization of two types of trypsin-like enzymes
RT   from sperm of the ascidian (Prochordata) Halocynthia roretzi. Evidence for
RT   the presence of spermosin, a novel acrosin-like enzyme.";
RL   J. Biol. Chem. 259:2900-2904(1984).
RN   [4] {ECO:0000305}
RP   FUNCTION, SUBCELLULAR LOCATION, TISSUE SPECIFICITY, AND DEVELOPMENTAL
RP   STAGE.
RX   PubMed=8670234; DOI=10.1006/bbrc.1996.0773;
RA   Sawada H., Iwasaki K., Kihara-Negishi F., Ariga H., Yokosawa H.;
RT   "Localization, expression, and the role in fertilization of spermosin, an
RT   ascidian sperm trypsin-like protease.";
RL   Biochem. Biophys. Res. Commun. 222:499-504(1996).
RN   [5] {ECO:0000305}
RP   FUNCTION, CATALYTIC ACTIVITY, AND ACTIVITY REGULATION.
RX   PubMed=8914083;
RX   DOI=10.1002/(sici)1098-2795(199610)45:2<240::aid-mrd18>3.0.co;2-4;
RA   Sawada H., Someno T.;
RT   "Substrate specificity of ascidian sperm trypsin-like proteases, spermosin
RT   and acrosin.";
RL   Mol. Reprod. Dev. 45:240-243(1996).
CC   -!- FUNCTION: Trypsin-like protease with a narrow substrate specificity.
CC       Preferentially hydrolyzes substrates with Pro in the P2 position and
CC       Val in the P3 position. Plays a role in fertilization.
CC       {ECO:0000269|PubMed:6365918, ECO:0000269|PubMed:8670234,
CC       ECO:0000269|PubMed:8914083}.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=Hydrolyzes arginyl bonds, preferably with Pro in the P2
CC         position.; EC=3.4.21.99; Evidence={ECO:0000269|PubMed:6365918,
CC         ECO:0000269|PubMed:8914083};
CC   -!- ACTIVITY REGULATION: Inhibited by peptidyl-argininals wth Pro in the P2
CC       position, diisopropyl fluorophosphate, phenylmethanesulfonyl fluoride,
CC       leupeptin, antipain, soybean trypsin inhibitor, aprotinin, ovomucoid,
CC       valyl-prolyl-arginyl-chloromethane, glycyl-valyl-arginyl-chloromethane,
CC       p-aminobenzamidine, benzamidine, zinc chloride and mercuric chloride.
CC       {ECO:0000269|PubMed:6365918, ECO:0000269|PubMed:6381175,
CC       ECO:0000269|PubMed:8914083}.
CC   -!- BIOPHYSICOCHEMICAL PROPERTIES:
CC       Kinetic parameters:
CC         KM=145 uM for Boc-Val-Pro-Arg-MCA {ECO:0000269|PubMed:6365918};
CC       pH dependence:
CC         Optimum pH is 8.5-9.0. {ECO:0000269|PubMed:6365918};
CC   -!- SUBUNIT: Heterodimer of a heavy chain and either an L1 light chain or
CC       an L2 light chain linked by a disulfide bond.
CC       {ECO:0000269|PubMed:11856325}.
CC   -!- SUBCELLULAR LOCATION: Secreted {ECO:0000269|PubMed:8670234}.
CC       Note=Localized on the sperm head. Released into the surrounding
CC       seawater in response to the sperm reaction, a large proportion remains
CC       associated with the sperm cell surface. {ECO:0000269|PubMed:8670234}.
CC   -!- TISSUE SPECIFICITY: Detected in sperm, but not in unfertilized eggs (at
CC       protein level). Expressed in gonad, but not in hepatopancreas,
CC       intestine or branchial basket. {ECO:0000269|PubMed:11856325,
CC       ECO:0000269|PubMed:8670234}.
CC   -!- DEVELOPMENTAL STAGE: Expression begins about half a month before the
CC       start of the spawning season (early December), and continues throughout
CC       the spawning season. {ECO:0000269|PubMed:8670234}.
CC   -!- SIMILARITY: Belongs to the peptidase S1 family. {ECO:0000255|PROSITE-
CC       ProRule:PRU00274}.
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DR   EMBL; AB052776; BAB60896.1; -; mRNA.
DR   AlphaFoldDB; Q966V2; -.
DR   SMR; Q966V2; -.
DR   MEROPS; S01.082; -.
DR   KEGG; ag:BAB60896; -.
DR   BRENDA; 3.4.21.99; 2564.
DR   GO; GO:0005576; C:extracellular region; IEA:UniProtKB-SubCell.
DR   GO; GO:0004252; F:serine-type endopeptidase activity; IEA:InterPro.
DR   GO; GO:0006508; P:proteolysis; IEA:UniProtKB-KW.
DR   CDD; cd00190; Tryp_SPc; 1.
DR   Gene3D; 2.40.10.10; -; 1.
DR   InterPro; IPR009003; Peptidase_S1_PA.
DR   InterPro; IPR043504; Peptidase_S1_PA_chymotrypsin.
DR   InterPro; IPR001314; Peptidase_S1A.
DR   InterPro; IPR001254; Trypsin_dom.
DR   InterPro; IPR018114; TRYPSIN_HIS.
DR   InterPro; IPR033116; TRYPSIN_SER.
DR   Pfam; PF00089; Trypsin; 1.
DR   PRINTS; PR00722; CHYMOTRYPSIN.
DR   SMART; SM00020; Tryp_SPc; 1.
DR   SUPFAM; SSF50494; SSF50494; 1.
DR   PROSITE; PS50240; TRYPSIN_DOM; 1.
DR   PROSITE; PS00134; TRYPSIN_HIS; 1.
DR   PROSITE; PS00135; TRYPSIN_SER; 1.
PE   1: Evidence at protein level;
KW   Direct protein sequencing; Disulfide bond; Hydrolase; Protease; Secreted;
KW   Serine protease; Signal.
FT   SIGNAL          1..22
FT                   /evidence="ECO:0000269|PubMed:11856325"
FT   CHAIN           23..129
FT                   /note="Spermosin L1 light chain"
FT                   /evidence="ECO:0000269|PubMed:11856325"
FT                   /id="PRO_0000395364"
FT   CHAIN           97..127
FT                   /note="Spermosin L2 light chain"
FT                   /evidence="ECO:0000269|PubMed:11856325"
FT                   /id="PRO_0000395365"
FT   CHAIN           130..388
FT                   /note="Spermosin heavy chain"
FT                   /evidence="ECO:0000269|PubMed:11856325"
FT                   /id="PRO_0000395366"
FT   DOMAIN          130..372
FT                   /note="Peptidase S1"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00274"
FT   REGION          29..98
FT                   /note="Disordered"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   COMPBIAS        29..44
FT                   /note="Polar residues"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   COMPBIAS        45..86
FT                   /note="Pro residues"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   ACT_SITE        178
FT                   /note="Charge relay system"
FT                   /evidence="ECO:0000250|UniProtKB:Q9CR35"
FT   ACT_SITE        231
FT                   /note="Charge relay system"
FT                   /evidence="ECO:0000250|UniProtKB:Q9CR35"
FT   ACT_SITE        324
FT                   /note="Charge relay system"
FT                   /evidence="ECO:0000250|UniProtKB:Q9CR35"
FT   DISULFID        116..251
FT                   /note="Interchain (between light and heavy chains)"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00274,
FT                   ECO:0000269|PubMed:11856325"
FT   DISULFID        163..179
FT                   /evidence="ECO:0000250|UniProtKB:Q9CR35,
FT                   ECO:0000255|PROSITE-ProRule:PRU00274"
FT   DISULFID        265..330
FT                   /evidence="ECO:0000250|UniProtKB:Q9CR35,
FT                   ECO:0000255|PROSITE-ProRule:PRU00274"
FT   DISULFID        295..310
FT                   /evidence="ECO:0000250|UniProtKB:Q9CR35,
FT                   ECO:0000255|PROSITE-ProRule:PRU00274"
FT   DISULFID        320..349
FT                   /evidence="ECO:0000250|UniProtKB:Q9CR35,
FT                   ECO:0000255|PROSITE-ProRule:PRU00274"
SQ   SEQUENCE   388 AA;  42145 MW;  5F61BDE7588AD96C CRC64;
     MAAINVIFIS GAIALFALTG SCSESTNPFT NKPYATQNPY SPPQTNQPTK RPYQPGPAPT
     PAPYIPQKTN PPTKRPLNPT PSPTAKPPSE NSESENSEGP VLIEEDHFTV DANFKCGIPP
     VEPDLKKGKI VGGAEAVPNS WPYAAAFGTY DISGGKLEVS QMCGSTIITP RHALTAAHCF
     MMDPDIDQTY YIFMGLHDET TYKGVRPNKI VGVRYHPKTN VFTDDPWLVY DFAILTLRKK
     VIANFAWNYA CLPQPKKIPP EGTICWSVGW GVTQNTGGDN VLKQVAIDLV SEKRCKEEYR
     STITSKSTIC GGTTPGQDTC QGDSGGPLFC KEDGKWYLQG IVSYGPSVCG SGPMAAYAAV
     AYNLEWLCCY MPNLPSCEDI ECDESGEN