ID   PIF_PINFU               Reviewed;        1007 AA.
AC   C7G0B5;
DT   24-NOV-2009, integrated into UniProtKB/Swiss-Prot.
DT   13-OCT-2009, sequence version 1.
DT   25-MAY-2022, entry version 39.
DE   RecName: Full=Protein PIF;
DE   Contains:
DE     RecName: Full=Protein Pif97;
DE   Contains:
DE     RecName: Full=Protein Pif80;
DE     AltName: Full=Aragonite-binding protein;
DE   Flags: Precursor;
OS   Pinctada fucata (Akoya pearl oyster) (Pinctada imbricata fucata).
OC   Eukaryota; Metazoa; Spiralia; Lophotrochozoa; Mollusca; Bivalvia;
OC   Autobranchia; Pteriomorphia; Pterioida; Pterioidea; Pteriidae; Pinctada.
OX   NCBI_TaxID=50426;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [MRNA], PROTEIN SEQUENCE OF 548-564 AND 815-842,
RP   SUBUNIT, AND FUNCTION.
RC   TISSUE=Mantle;
RX   PubMed=19679771; DOI=10.1126/science.1173793;
RA   Suzuki M., Saruwatari K., Kogure T., Yamamoto Y., Nishimura T., Kato T.,
RA   Nagasawa H.;
RT   "An acidic matrix protein, Pif, is a key macromolecule for nacre
RT   formation.";
RL   Science 325:1388-1390(2009).
RN   [2]
RP   FUNCTION.
RX   PubMed=19679772; DOI=10.1126/science.1177055;
RA   Kroger N.;
RT   "The molecular basis of nacre formation.";
RL   Science 325:1351-1352(2009).
CC   -!- FUNCTION: Essential component of the organic matrix for normal growth
CC       of the nacreous layer. The complex contributes to the initiation of
CC       aragonite crystallization as well as subsequenct stacking of aragonite
CC       tablets in the nacreous layer.
CC   -!- FUNCTION: Pif80 binds to both aragonite and calcite crystals, with a
CC       higher specificity to aragonite crystals.
CC   -!- FUNCTION: Pif97 contains a chitin-binding domain that allows for
CC       attachment of the entire complex to the chitin-containing organic
CC       framework.
CC   -!- SUBUNIT: Heterooligomer; disulfide-linked. Pif97, Pif80, N16 and other
CC       proteins form a complex. {ECO:0000269|PubMed:19679771}.
CC   -!- SUBCELLULAR LOCATION: Secreted, extracellular space, extracellular
CC       matrix.
CC   -!- TISSUE SPECIFICITY: Component of conchiolin, the organic matrix of
CC       nacre. Expressed at extremely high levels in the dorsal region of the
CC       mantle, which region may be responsible for the nacreous layer
CC       formation, but only in trace amounts at the mantle edge, which region
CC       may be responsible for the prismatic layer formation.
CC   -!- MISCELLANEOUS: Pif80 and Pif97 are rich in Asp. This amino-acid appears
CC       to be common to biomineral-forming organisms.
CC   -!- WEB RESOURCE: Name=Protein Spotlight; Note=String of intrusion - Issue
CC       112 of December 2009;
CC       URL="https://web.expasy.org/spotlight/back_issues/112";
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DR   EMBL; AB236929; BAH97338.1; -; mRNA.
DR   AlphaFoldDB; C7G0B5; -.
DR   SMR; C7G0B5; -.
DR   PRIDE; C7G0B5; -.
DR   GO; GO:0005576; C:extracellular region; IEA:UniProtKB-KW.
DR   GO; GO:0008061; F:chitin binding; IEA:InterPro.
DR   Gene3D; 3.40.50.410; -; 1.
DR   InterPro; IPR002557; Chitin-bd_dom.
DR   InterPro; IPR036508; Chitin-bd_dom_sf.
DR   InterPro; IPR002035; VWF_A.
DR   InterPro; IPR036465; vWFA_dom_sf.
DR   Pfam; PF00092; VWA; 1.
DR   SMART; SM00494; ChtBD2; 2.
DR   SMART; SM00327; VWA; 1.
DR   SUPFAM; SSF53300; SSF53300; 1.
DR   SUPFAM; SSF57625; SSF57625; 1.
DR   PROSITE; PS50940; CHIT_BIND_II; 2.
DR   PROSITE; PS50234; VWFA; 1.
PE   1: Evidence at protein level;
KW   Direct protein sequencing; Disulfide bond; Extracellular matrix; Repeat;
KW   Secreted; Signal.
FT   SIGNAL          1..22
FT                   /evidence="ECO:0000255"
FT   CHAIN           23..547
FT                   /note="Protein Pif97"
FT                   /id="PRO_5000503552"
FT   CHAIN           548..1007
FT                   /note="Protein Pif80"
FT                   /id="PRO_5000503553"
FT   DOMAIN          29..202
FT                   /note="VWFA"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00219"
FT   DOMAIN          255..372
FT                   /note="Chitin-binding type-2"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00144"
FT   REGION          212..244
FT                   /note="Disordered"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   REGION          377..401
FT                   /note="Disordered"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   REGION          544..547
FT                   /note="Kex2-like proteinase cleavage site"
FT   REGION          588..634
FT                   /note="Disordered"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   REGION          651..792
FT                   /note="Disordered"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   REGION          854..983
FT                   /note="Disordered"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   COMPBIAS        377..396
FT                   /note="Acidic residues"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   COMPBIAS        588..627
FT                   /note="Basic and acidic residues"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   COMPBIAS        666..792
FT                   /note="Basic and acidic residues"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   COMPBIAS        856..875
FT                   /note="Acidic residues"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   COMPBIAS        876..983
FT                   /note="Basic and acidic residues"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   DISULFID        296..309
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00144"
FT   DISULFID        352..364
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00144"
SQ   SEQUENCE   1007 AA;  115355 MW;  A4C31FD25964F52B CRC64;
     MQVPSIRVVF LLTAVFCVGV KSDECKTADV VVNVDASDDV SDQDFDKLKR AMLMMVRGLS
     IDDNQIRLGM VTYGSEVCDS IPLQGDRLDL ARTIRYMKKP TGPSKPFKGM GEARRMFSSR
     GRYNVPHITM NLGGDIVDTE VKDLMDETDK ARDEDIKVMA IGLGAKVDRD EIESIAYDRD
     QAYFMDDEDD LIRKVKEIPD YLCKIIKAKK PKVSGGKKSK PAKKVDNGPA GKSPGFDALK
     QSDDKSDKAK KVEVKELCDD AEWVDGVGYG SVPTRCEDFV MCQNVSGSLR KTLKSCPFGQ
     YWSKRQTSCV LTEDEDCSDD LCKTMLLPSR EYDVSCRAYW KCEKGKSVAR CCPSGMAYEP
     GKGCVLDLDC DEECPPKNDG DDDDDSSDED DDDEIEYNPN CPLRPIKGHP EKFKQHTGDD
     NWEDFDCAPG TLFSARDCAC SILGTAKKDD KNDDGGDAHK VCEPELYLPF CDDLHDYSGK
     ETHVENEGDA VIIENGKAYF NGRAGLKIPR FSGVPYGKSV FIKMKYKEDE DDDKNKNDDD
     KKLRMKRDER SRKDYLKAIL KRDDRKDKTD DTKGRRIIDR NDIIDDRRGR RKDDRKDGGR
     DDGKDGRRDD RKDNRLDDIK DKNDEPMTLI SNGECDNFEL NDCFEKPSIA ITTGKKSAGF
     SVTSSEKDEV DLEIDEDKKG YLWDKEDGPD RNGKDKDRNG DRSDDRRGYY WKKKDKDDNG
     KDKDKKGDKS DDKKGYYWKK DKDDKNGKDK DKRRDKSDDK KSLDDIVREI ERSKGNGKDD
     NKDDEDDDKK GWKTVSLKIS NGHIRGRRDD REDKDVLDGD LKTTFSGFQI GQGASNKNFK
     GYMDEVYIYF CDPGKEADYD DEDDDDDDDD SDENDKNDDK KDGKKTDDKD KKDRKDGRDD
     RKDGRDDRKD RRDDRKDDRK GGKDDRKDDR KGGKDDRKDG RDVRDDRDRG DKYDKKDDKD
     NDRLSDKDDR KDVDDNDKDD DNEKLYKRAM KKCDYVNKNV AKWLDKR