ID   PSPB_BOVIN              Reviewed;         373 AA.
AC   P15781; Q148E8;
DT   01-APR-1990, integrated into UniProtKB/Swiss-Prot.
DT   01-MAY-2007, sequence version 3.
DT   27-MAR-2024, entry version 147.
DE   RecName: Full=Pulmonary surfactant-associated protein B;
DE            Short=SP-B;
DE   AltName: Full=6 kDa protein;
DE   AltName: Full=Pulmonary surfactant-associated proteolipid SPL(Phe);
DE   Flags: Precursor;
GN   Name=SFTPB; Synonyms=SFTP3;
OS   Bos taurus (Bovine).
OC   Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi; Mammalia;
OC   Eutheria; Laurasiatheria; Artiodactyla; Ruminantia; Pecora; Bovidae;
OC   Bovinae; Bos.
OX   NCBI_TaxID=9913;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE MRNA].
RC   STRAIN=Hereford; TISSUE=Fetal lung;
RG   NIH - Mammalian Gene Collection (MGC) project;
RL   Submitted (JUN-2006) to the EMBL/GenBank/DDBJ databases.
RN   [2]
RP   PROTEIN SEQUENCE OF 188-266.
RX   PubMed=3689402; DOI=10.1016/s0006-291x(87)80288-7;
RA   Olafson R.W., Rink U., Kielland S., Yu S.-H., Chung J., Harding P.G.R.,
RA   Possmayer F.;
RT   "Protein sequence analysis studies on the low molecular weight hydrophobic
RT   proteins associated with bovine pulmonary surfactant.";
RL   Biochem. Biophys. Res. Commun. 148:1406-1411(1987).
RN   [3]
RP   PROTEIN SEQUENCE OF 188-266, AND IDENTIFICATION BY MASS SPECTROMETRY.
RX   PubMed=18088070; DOI=10.1002/rcm.3345;
RA   Liu S., Zhao L., Manzanares D., Doherty-Kirby A., Zhang C., Possmayer F.,
RA   Lajoie G.A.;
RT   "Characterization of bovine surfactant proteins B and C by electrospray
RT   ionization mass spectrometry.";
RL   Rapid Commun. Mass Spectrom. 22:197-203(2008).
RN   [4]
RP   PROTEIN SEQUENCE OF 188-197.
RX   PubMed=3663690; DOI=10.1016/0005-2760(87)90070-1;
RA   Yu S.-H., Chung W., Olafson R.W., Harding P.G.R., Possmayer F.;
RT   "Characterization of the small hydrophobic proteins associated with
RT   pulmonary surfactant.";
RL   Biochim. Biophys. Acta 921:437-448(1987).
CC   -!- FUNCTION: Pulmonary surfactant-associated proteins promote alveolar
CC       stability by lowering the surface tension at the air-liquid interface
CC       in the peripheral air spaces. SP-B increases the collapse pressure of
CC       palmitic acid to nearly 70 millinewtons per meter.
CC   -!- SUBUNIT: Homodimer; disulfide-linked.
CC   -!- SUBCELLULAR LOCATION: Secreted, extracellular space, surface film.
CC   -!- MISCELLANEOUS: Pulmonary surfactant consists of 90% lipid and 10%
CC       protein. There are 4 surfactant-associated proteins: 2 collagenous,
CC       carbohydrate-binding glycoproteins (SP-A and SP-D) and 2 small
CC       hydrophobic proteins (SP-B and SP-C).
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DR   EMBL; BC118395; AAI18396.1; -; mRNA.
DR   PIR; A29667; A29667.
DR   RefSeq; NP_001068779.1; NM_001075311.2.
DR   RefSeq; XP_005212817.1; XM_005212760.2.
DR   AlphaFoldDB; P15781; -.
DR   SMR; P15781; -.
DR   STRING; 9913.ENSBTAP00000042549; -.
DR   GlyCosmos; P15781; 2 sites, No reported glycans.
DR   PaxDb; 9913-ENSBTAP00000042549; -.
DR   Ensembl; ENSBTAT00000045134.4; ENSBTAP00000042549.3; ENSBTAG00000021230.6.
DR   GeneID; 507398; -.
DR   KEGG; bta:507398; -.
DR   CTD; 6439; -.
DR   VEuPathDB; HostDB:ENSBTAG00000021230; -.
DR   VGNC; VGNC:34528; SFTPB.
DR   eggNOG; KOG1340; Eukaryota.
DR   GeneTree; ENSGT00940000161711; -.
DR   HOGENOM; CLU_063244_0_0_1; -.
DR   InParanoid; P15781; -.
DR   OMA; PKFWCQS; -.
DR   OrthoDB; 7299at2759; -.
DR   TreeFam; TF316942; -.
DR   Reactome; R-BTA-5683826; Surfactant metabolism.
DR   Proteomes; UP000009136; Chromosome 11.
DR   Bgee; ENSBTAG00000021230; Expressed in lung and 10 other cell types or tissues.
DR   GO; GO:0097208; C:alveolar lamellar body; IBA:GO_Central.
DR   GO; GO:0005576; C:extracellular region; IEA:UniProtKB-SubCell.
DR   GO; GO:0005764; C:lysosome; IEA:InterPro.
DR   GO; GO:0005771; C:multivesicular body; IBA:GO_Central.
DR   GO; GO:0007585; P:respiratory gaseous exchange by respiratory system; IEA:UniProtKB-KW.
DR   GO; GO:0006665; P:sphingolipid metabolic process; IEA:InterPro.
DR   Gene3D; 1.10.225.10; Saposin-like; 2.
DR   InterPro; IPR003119; SAP_A.
DR   InterPro; IPR008138; SapB_2.
DR   InterPro; IPR008373; Saposin.
DR   InterPro; IPR011001; Saposin-like.
DR   InterPro; IPR008139; SaposinB_dom.
DR   PANTHER; PTHR11480:SF33; PULMONARY SURFACTANT-ASSOCIATED PROTEIN B; 1.
DR   PANTHER; PTHR11480; SAPOSIN-RELATED; 1.
DR   Pfam; PF02199; SapA; 1.
DR   Pfam; PF03489; SapB_2; 2.
DR   PRINTS; PR01797; SAPOSIN.
DR   SMART; SM00162; SAPA; 1.
DR   SMART; SM00741; SapB; 3.
DR   SUPFAM; SSF47862; Saposin; 2.
DR   PROSITE; PS51110; SAP_A; 1.
DR   PROSITE; PS50015; SAP_B; 3.
PE   1: Evidence at protein level;
KW   Direct protein sequencing; Disulfide bond; Gaseous exchange; Glycoprotein;
KW   Reference proteome; Repeat; Secreted; Signal; Surface film.
FT   SIGNAL          1..22
FT                   /evidence="ECO:0000255"
FT   PROPEP          23..187
FT                   /id="PRO_0000285124"
FT   CHAIN           188..266
FT                   /note="Pulmonary surfactant-associated protein B"
FT                   /id="PRO_0000175240"
FT   PROPEP          267..373
FT                   /id="PRO_0000285125"
FT   DOMAIN          24..64
FT                   /note="Saposin A-type"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00414"
FT   DOMAIN          64..146
FT                   /note="Saposin B-type 1"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00415"
FT   DOMAIN          191..268
FT                   /note="Saposin B-type 2"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00415"
FT   DOMAIN          287..362
FT                   /note="Saposin B-type 3"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00415"
FT   CARBOHYD        73
FT                   /note="N-linked (GlcNAc...) asparagine"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00415"
FT   CARBOHYD        303
FT                   /note="N-linked (GlcNAc...) asparagine"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00415"
FT   DISULFID        68..142
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00415"
FT   DISULFID        71..136
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00415"
FT   DISULFID        99..111
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00415"
FT   DISULFID        195..264
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00415"
FT   DISULFID        198..258
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00415"
FT   DISULFID        222..233
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00415"
FT   DISULFID        235
FT                   /note="Interchain"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00415"
FT   DISULFID        291..358
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00415"
FT   DISULFID        294..352
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00415"
FT   DISULFID        317..327
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00415"
FT   CONFLICT        198
FT                   /note="C -> L (in Ref. 2; AA sequence)"
FT                   /evidence="ECO:0000305"
FT   CONFLICT        204
FT                   /note="R -> K (in Ref. 2; AA sequence)"
FT                   /evidence="ECO:0000305"
FT   CONFLICT        233..239
FT                   /note="CQCLVER -> IQQLVIE (in Ref. 2; AA sequence)"
FT                   /evidence="ECO:0000305"
FT   CONFLICT        245
FT                   /note="L -> LT (in Ref. 2; AA sequence)"
FT                   /evidence="ECO:0000305"
FT   CONFLICT        252
FT                   /note="Missing (in Ref. 2; AA sequence)"
FT                   /evidence="ECO:0000305"
FT   CONFLICT        255
FT                   /note="Q -> N (in Ref. 2; AA sequence)"
FT                   /evidence="ECO:0000305"
FT   CONFLICT        261
FT                   /note="V -> R (in Ref. 2; AA sequence)"
FT                   /evidence="ECO:0000305"
FT   CONFLICT        266
FT                   /note="S -> G (in Ref. 2; AA sequence)"
FT                   /evidence="ECO:0000305"
SQ   SEQUENCE   373 AA;  41060 MW;  A41A31AE5A5C0F82 CRC64;
     MAKSHLLPWL LLLPILCGPG TAAAITYSLA CAQGPEFWCQ SLEQALQCRA LGHCLQEVWG
     HVEADDLCQE CENISRLLTK MAKEAIFQDS VRKFLEQECD VLPLKLLAPL CRHLLDTYFP
     LIIEHFQSHM NPKFICQHVG LCKPRHPEPG KGPEPWGPLL DKLALPLLPG VPQAKPGPQT
     QDLSEQLFPI PIPYCWLCRT LIKRIQAVIP KGVLAMTVAQ VCHVVPLLVG GICQCLVERY
     SVILLDTLLG RMLPQLVCGL VLRCSSEDSA GPALPALGSV PGEWLPQDSD CQLCMFVTTQ
     AGNSSEQATP QAMRQACLGT WLDRQKCERF VEENAPRLQT LVSSGWDAHM ACQALGTCAA
     PFSPLQCVHS PHF
//