C7G0B5 (PIF_PINFU) Reviewed, UniProtKB/Swiss-Prot

Names and origin

Protein names	Recommended name: Protein PIF Cleaved into the following 2 chains: Protein Pif97 Protein Pif80 Alternative name(s): Aragonite-binding protein
Organism	Pinctada fucata (Pearl oyster)
Taxonomic identifier	50426 [NCBI]
Taxonomic lineage	cellular organisms › Eukaryota › Opisthokonta › Metazoa › Eumetazoa › Bilateria › Protostomia › Lophotrochozoa › Mollusca › Bivalvia › Pteriomorphia › Pterioida › Pterioidea › Pteriidae › Pinctada

Protein attributes

Sequence length	1007 AA.
Sequence status	Complete.
Sequence processing	The displayed sequence is further processed into a mature form.
Protein existence	Evidence at protein level

General annotation (Comments)

Function	Essential component of the organic matrix for normal growth of the nacreous layer. The complex takes part in the initiation of aragonite crystallization as well as subsequenct stacking of aragonite tablets in the nacreous layer. Ref.1 Ref.2 Pif80 binds to both aragonite and calcite crystals, with a higher specificity to aragonite crystals. Ref.1 Ref.2 Pif97 contains a chitin-binding domain that allows for attachment of the entire complex to the chitin-containing organic framework. Ref.1 Ref.2
Subunit structure	Heterooligomer; disulfide-linked. Pif97, Pif80, N16 and other proteins form a complex. Ref.1
Subcellular location	Secreted › extracellular space › extracellular matrix.
Tissue specificity	Component of conchiolin, the organic matrix of nacre. Expressed at extremely high levels in the dorsal region of the mantle, which region may be responsible for the nacreous layer formation, but only in trace amounts at the mantle edge, which region may be responsible for the prismatic layer formation.
Miscellaneous	Pif80 and Pif97 are rich in Asp. This amino-acid appears to be common to biomineral-forming organisms.
Sequence similarities	Contains 1 chitin-binding type-2 domain. Contains 1 VWFA domain.

Ontologies

Keywords
Cellular component	Extracellular matrix Secreted
Domain	Repeat Signal
PTM	Disulfide bond
Technical term	Direct protein sequencing
Gene Ontology (GO)
Biological_process	chitin metabolic process Inferred from electronic annotation. Source: InterPro
Cellular_component	proteinaceous extracellular matrix Inferred from electronic annotation. Source: UniProtKB-SubCell
Molecular_function	chitin binding Inferred from electronic annotation. Source: InterPro
Complete GO annotation...

Sequence annotation (Features)

	Feature key	Position(s)	Length	Description	Graphical view	Feature identifier
Molecule processing
	Signal peptide	1 – 22	22	Potential
	Chain	23 – 547	525	Protein Pif97		PRO_5000503552
	Chain	548 – 1007	460	Protein Pif80		PRO_5000503553
Regions
	Domain	29 – 202	174	VWFA
	Domain	255 – 372	118	Chitin-binding type-2
	Region	544 – 547	4	Kex2-like proteinase cleavage site
	Compositional bias	367 – 981	615	Asp-rich
	Compositional bias	379 – 385	7	Poly-Asp
	Compositional bias	388 – 393	6	Poly-Asp
	Compositional bias	858 – 872	15	Poly-Asp
Amino acid modifications
	Disulfide bond	296 ↔ 309		By similarity
	Disulfide bond	352 ↔ 364		By similarity

Sequences

	Sequence		Length	Mass (Da)
	C7G0B5 [UniParc]. Last modified October 13, 2009. Version 1. Checksum: A4C31FD25964F52B	FASTA	1,007	115,355
	10 20 30 40 50 60 MQVPSIRVVF LLTAVFCVGV KSDECKTADV VVNVDASDDV SDQDFDKLKR AMLMMVRGLS 70 80 90 100 110 120 IDDNQIRLGM VTYGSEVCDS IPLQGDRLDL ARTIRYMKKP TGPSKPFKGM GEARRMFSSR 130 140 150 160 170 180 GRYNVPHITM NLGGDIVDTE VKDLMDETDK ARDEDIKVMA IGLGAKVDRD EIESIAYDRD 190 200 210 220 230 240 QAYFMDDEDD LIRKVKEIPD YLCKIIKAKK PKVSGGKKSK PAKKVDNGPA GKSPGFDALK 250 260 270 280 290 300 QSDDKSDKAK KVEVKELCDD AEWVDGVGYG SVPTRCEDFV MCQNVSGSLR KTLKSCPFGQ 310 320 330 340 350 360 YWSKRQTSCV LTEDEDCSDD LCKTMLLPSR EYDVSCRAYW KCEKGKSVAR CCPSGMAYEP 370 380 390 400 410 420 GKGCVLDLDC DEECPPKNDG DDDDDSSDED DDDEIEYNPN CPLRPIKGHP EKFKQHTGDD 430 440 450 460 470 480 NWEDFDCAPG TLFSARDCAC SILGTAKKDD KNDDGGDAHK VCEPELYLPF CDDLHDYSGK 490 500 510 520 530 540 ETHVENEGDA VIIENGKAYF NGRAGLKIPR FSGVPYGKSV FIKMKYKEDE DDDKNKNDDD 550 560 570 580 590 600 KKLRMKRDER SRKDYLKAIL KRDDRKDKTD DTKGRRIIDR NDIIDDRRGR RKDDRKDGGR 610 620 630 640 650 660 DDGKDGRRDD RKDNRLDDIK DKNDEPMTLI SNGECDNFEL NDCFEKPSIA ITTGKKSAGF 670 680 690 700 710 720 SVTSSEKDEV DLEIDEDKKG YLWDKEDGPD RNGKDKDRNG DRSDDRRGYY WKKKDKDDNG 730 740 750 760 770 780 KDKDKKGDKS DDKKGYYWKK DKDDKNGKDK DKRRDKSDDK KSLDDIVREI ERSKGNGKDD 790 800 810 820 830 840 NKDDEDDDKK GWKTVSLKIS NGHIRGRRDD REDKDVLDGD LKTTFSGFQI GQGASNKNFK 850 860 870 880 890 900 GYMDEVYIYF CDPGKEADYD DEDDDDDDDD SDENDKNDDK KDGKKTDDKD KKDRKDGRDD 910 920 930 940 950 960 RKDGRDDRKD RRDDRKDDRK GGKDDRKDDR KGGKDDRKDG RDVRDDRDRG DKYDKKDDKD 970 980 990 1000 NDRLSDKDDR KDVDDNDKDD DNEKLYKRAM KKCDYVNKNV AKWLDKR

References

[1]	"An acidic matrix protein, Pif, is a key macromolecule for nacre formation." Suzuki M., Saruwatari K., Kogure T., Yamamoto Y., Nishimura T., Kato T., Nagasawa H. Science 325:1388-1390(2009) [PubMed] [Europe PMC] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [MRNA], PROTEIN SEQUENCE OF 548-564 AND 815-842, SUBUNIT, FUNCTION. Tissue: Mantle.
[2]	"The molecular basis of nacre formation." Kroger N. Science 325:1351-1352(2009) [PubMed] [Europe PMC] [Abstract] Cited for: FUNCTION.

Web resources

Protein Spotlight

String of intrusion - Issue 112 of December 2009

Cross-references

Sequence databases
EMBL GenBank DDBJ	AB236929 mRNA. Translation: BAH97338.1.
3D structure databases
ModBase	Search...
Protocols and materials databases
StructuralBiologyKnowledgebase	Search...
Family and domain databases
Gene3D	2.170.140.10. 1 hit.
InterPro	IPR002557. Chitin-bd_dom. IPR002035. VWF_A. [Graphical view]
Pfam	PF00092. VWA. 1 hit. [Graphical view]
SMART	SM00494. ChtBD2. 2 hits. SM00327. VWA. 1 hit. [Graphical view]
SUPFAM	SSF57625. Chitin_bind_PerA. 1 hit.
PROSITE	PS50940. CHIT_BIND_II. 2 hits. PS50234. VWFA. 1 hit. [Graphical view]
ProtoNet	Search...

Entry information

Entry name

PIF_PINFU

Accession

Primary (citable) accession number: C7G0B5

Entry history

Integrated into UniProtKB/Swiss-Prot:	November 24, 2009
Last sequence update:	October 13, 2009
Last modified:	March 6, 2013
This is version 15 of the entry and version 1 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)