ID   ANP1_ZOAAM              Reviewed;          64 AA.
AC   P19608;
DT   01-FEB-1991, integrated into UniProtKB/Swiss-Prot.
DT   01-FEB-1991, sequence version 1.
DT   25-MAY-2022, entry version 89.
DE   RecName: Full=Ice-structuring protein SP2(HPLC 1);
DE            Short=ISP SP2(HPLC 1);
DE   AltName: Full=Antifreeze protein SP2(HPLC 1);
OS   Zoarces americanus (Ocean pout) (Macrozoarces americanus).
OC   Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi;
OC   Actinopterygii; Neopterygii; Teleostei; Neoteleostei; Acanthomorphata;
OC   Eupercaria; Perciformes; Cottioidei; Zoarcales; Zoarcidae; Zoarcinae;
OC   Zoarces.
OX   NCBI_TaxID=8199;
RN   [1]
RP   PROTEIN SEQUENCE, SUBCELLULAR LOCATION, AND TISSUE SPECIFICITY.
RX   PubMed=3403560; DOI=10.1016/s0021-9258(18)37891-8;
RA   Hew C.-L., Wang N.-C., Joshi S., Fletcher G.L., Scott G.K., Hayes P.H.,
RA   Buettner B., Davies P.L.;
RT   "Multiple genes provide the basis for antifreeze protein diversity and
RT   dosage in the ocean pout, Macrozoarces americanus.";
RL   J. Biol. Chem. 263:12049-12055(1988).
RN   [2]
RP   X-RAY CRYSTALLOGRAPHY (2.00 ANGSTROMS), SUBCELLULAR LOCATION, AND TISSUE
RP   SPECIFICITY.
RX   PubMed=9591641; DOI=10.1016/s0006-3495(98)77923-8;
RA   Yang D.S., Hon W.C., Bubanko S., Xue Y., Seetharaman J., Hew C.L.,
RA   Sicheri F.;
RT   "Identification of the ice-binding surface on a type III antifreeze protein
RT   with a 'flatness function' algorithm.";
RL   Biophys. J. 74:2142-2151(1998).
CC   -!- FUNCTION: Contributes to protect fish blood from freezing at subzero
CC       sea water temperatures. Lowers the blood freezing point. Binds to
CC       nascent ice crystals and prevents further growth (By similarity).
CC       {ECO:0000250}.
CC   -!- SUBCELLULAR LOCATION: Secreted {ECO:0000269|PubMed:3403560,
CC       ECO:0000269|PubMed:9591641}.
CC   -!- TISSUE SPECIFICITY: Detected in blood serum (at protein level).
CC       {ECO:0000269|PubMed:3403560, ECO:0000269|PubMed:9591641}.
CC   -!- SIMILARITY: Belongs to the type-III AFP family. {ECO:0000305}.
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DR   PIR; D31075; D31075.
DR   PDB; 1OPS; X-ray; 2.00 A; A=1-64.
DR   PDBsum; 1OPS; -.
DR   AlphaFoldDB; P19608; -.
DR   SMR; P19608; -.
DR   EvolutionaryTrace; P19608; -.
DR   GO; GO:0005576; C:extracellular region; IEA:UniProtKB-SubCell.
DR   InterPro; IPR006190; AFP_Neu5c_C.
DR   InterPro; IPR036732; AFP_Neu5c_C_sf.
DR   InterPro; IPR006013; Antifreeze_III.
DR   InterPro; IPR013974; SAF.
DR   Pfam; PF08666; SAF; 1.
DR   PRINTS; PR00357; ANTIFREEZIII.
DR   SMART; SM00858; SAF; 1.
DR   SUPFAM; SSF51269; SSF51269; 1.
DR   PROSITE; PS50844; AFP_LIKE; 1.
PE   1: Evidence at protein level;
KW   3D-structure; Antifreeze protein; Direct protein sequencing; Secreted.
FT   CHAIN           1..64
FT                   /note="Ice-structuring protein SP2(HPLC 1)"
FT                   /id="PRO_0000155155"
FT   DOMAIN          3..62
FT                   /note="AFP-like"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00021"
FT   SITE            8
FT                   /note="Important for ice-binding"
FT                   /evidence="ECO:0000250"
FT   SITE            13
FT                   /note="Important for ice-binding"
FT                   /evidence="ECO:0000250"
FT   SITE            17
FT                   /note="Important for ice-binding"
FT                   /evidence="ECO:0000250"
FT   SITE            43
FT                   /note="Important for ice-binding"
FT                   /evidence="ECO:0000250"
FT   STRAND          3..8
FT                   /evidence="ECO:0007829|PDB:1OPS"
FT   HELIX           18..20
FT                   /evidence="ECO:0007829|PDB:1OPS"
FT   STRAND          21..24
FT                   /evidence="ECO:0007829|PDB:1OPS"
FT   HELIX           33..38
FT                   /evidence="ECO:0007829|PDB:1OPS"
FT   TURN            39..41
FT                   /evidence="ECO:0007829|PDB:1OPS"
FT   STRAND          43..46
FT                   /evidence="ECO:0007829|PDB:1OPS"
FT   HELIX           56..58
FT                   /evidence="ECO:0007829|PDB:1OPS"
FT   TURN            60..63
FT                   /evidence="ECO:0007829|PDB:1OPS"
SQ   SEQUENCE   64 AA;  6775 MW;  DC6F90A2119FE0B0 CRC64;
     SQSVVATQLI PMNTALTPVM MEGKVTNPIG IPFAEMSQIV GKQVNTPVAK GQTIMPNMVK
     TYAA