ID   SPPA_HAEIN              Reviewed;         615 AA.
AC   P45243;
DT   01-NOV-1995, integrated into UniProtKB/Swiss-Prot.
DT   01-NOV-1995, sequence version 1.
DT   03-AUG-2022, entry version 131.
DE   RecName: Full=Protease 4;
DE            EC=3.4.21.-;
DE   AltName: Full=Endopeptidase IV;
DE   AltName: Full=Protease IV;
DE   AltName: Full=Signal peptide peptidase;
GN   Name=sppA; OrderedLocusNames=HI_1541;
OS   Haemophilus influenzae (strain ATCC 51907 / DSM 11121 / KW20 / Rd).
OC   Bacteria; Proteobacteria; Gammaproteobacteria; Pasteurellales;
OC   Pasteurellaceae; Haemophilus.
OX   NCBI_TaxID=71421;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=ATCC 51907 / DSM 11121 / KW20 / Rd;
RX   PubMed=7542800; DOI=10.1126/science.7542800;
RA   Fleischmann R.D., Adams M.D., White O., Clayton R.A., Kirkness E.F.,
RA   Kerlavage A.R., Bult C.J., Tomb J.-F., Dougherty B.A., Merrick J.M.,
RA   McKenney K., Sutton G.G., FitzHugh W., Fields C.A., Gocayne J.D.,
RA   Scott J.D., Shirley R., Liu L.-I., Glodek A., Kelley J.M., Weidman J.F.,
RA   Phillips C.A., Spriggs T., Hedblom E., Cotton M.D., Utterback T.R.,
RA   Hanna M.C., Nguyen D.T., Saudek D.M., Brandon R.C., Fine L.D.,
RA   Fritchman J.L., Fuhrmann J.L., Geoghagen N.S.M., Gnehm C.L., McDonald L.A.,
RA   Small K.V., Fraser C.M., Smith H.O., Venter J.C.;
RT   "Whole-genome random sequencing and assembly of Haemophilus influenzae
RT   Rd.";
RL   Science 269:496-512(1995).
RN   [2]
RP   IDENTIFICATION BY MASS SPECTROMETRY.
RC   STRAIN=ATCC 51907 / DSM 11121 / KW20 / Rd;
RX   PubMed=10675023;
RX   DOI=10.1002/(sici)1522-2683(20000101)21:2<411::aid-elps411>3.0.co;2-4;
RA   Langen H., Takacs B., Evers S., Berndt P., Lahm H.W., Wipf B., Gray C.,
RA   Fountoulakis M.;
RT   "Two-dimensional map of the proteome of Haemophilus influenzae.";
RL   Electrophoresis 21:411-429(2000).
CC   -!- FUNCTION: Digests cleaved signal peptides in vitro, its in vivo
CC       function is unknown. This activity is necessary to maintain proper
CC       secretion of mature proteins across the membrane (By similarity).
CC       {ECO:0000250}.
CC   -!- SUBUNIT: Homotetramer. {ECO:0000250}.
CC   -!- SUBCELLULAR LOCATION: Cell inner membrane {ECO:0000250}; Single-pass
CC       membrane protein {ECO:0000250}.
CC   -!- SIMILARITY: Belongs to the peptidase S49 family. {ECO:0000305}.
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DR   EMBL; L42023; AAC23191.1; -; Genomic_DNA.
DR   PIR; F64128; F64128.
DR   RefSeq; NP_439690.1; NC_000907.1.
DR   RefSeq; WP_005693566.1; NC_000907.1.
DR   AlphaFoldDB; P45243; -.
DR   SMR; P45243; -.
DR   STRING; 71421.HI_1541; -.
DR   EnsemblBacteria; AAC23191; AAC23191; HI_1541.
DR   KEGG; hin:HI_1541; -.
DR   PATRIC; fig|71421.8.peg.1612; -.
DR   eggNOG; COG0616; Bacteria.
DR   HOGENOM; CLU_008856_1_1_6; -.
DR   OMA; DPKGQYL; -.
DR   PhylomeDB; P45243; -.
DR   BioCyc; HINF71421:G1GJ1-1561-MON; -.
DR   Proteomes; UP000000579; Chromosome.
DR   GO; GO:0016021; C:integral component of membrane; IEA:UniProtKB-KW.
DR   GO; GO:0005886; C:plasma membrane; IEA:UniProtKB-SubCell.
DR   GO; GO:0008236; F:serine-type peptidase activity; IEA:UniProtKB-KW.
DR   GO; GO:0006465; P:signal peptide processing; IEA:InterPro.
DR   CDD; cd07023; S49_Sppa_N_C; 1.
DR   InterPro; IPR029045; ClpP/crotonase-like_dom_sf.
DR   InterPro; IPR004634; Pept_S49_pIV.
DR   InterPro; IPR004635; Pept_S49_SppA.
DR   InterPro; IPR002142; Peptidase_S49.
DR   Pfam; PF01343; Peptidase_S49; 2.
DR   PIRSF; PIRSF001217; Protease_4_SppA; 1.
DR   SUPFAM; SSF52096; SSF52096; 2.
DR   TIGRFAMs; TIGR00705; SppA_67K; 1.
DR   TIGRFAMs; TIGR00706; SppA_dom; 1.
PE   1: Evidence at protein level;
KW   Cell inner membrane; Cell membrane; Hydrolase; Membrane; Protease;
KW   Reference proteome; Serine protease; Transmembrane; Transmembrane helix.
FT   CHAIN           1..615
FT                   /note="Protease 4"
FT                   /id="PRO_0000171439"
FT   TOPO_DOM        1..17
FT                   /note="Cytoplasmic"
FT                   /evidence="ECO:0000255"
FT   TRANSMEM        18..38
FT                   /note="Helical"
FT                   /evidence="ECO:0000255"
FT   TOPO_DOM        39..615
FT                   /note="Periplasmic"
FT                   /evidence="ECO:0000255"
FT   ACT_SITE        201
FT                   /note="Proton donor/acceptor"
FT                   /evidence="ECO:0000250"
FT   ACT_SITE        405
FT                   /note="Nucleophile"
FT                   /evidence="ECO:0000250"
SQ   SEQUENCE   615 AA;  68057 MW;  60BE52496CFAAA3E CRC64;
     MFQVLKFCWK VLCFIRDLVM NVVFLGFVLL LVAIISFSSG GKKSTALTSE GALLLNLDGY
     LADNRDETLR WQDALSELNG EHVPRKISTF DVVFAIQQAE DDPKIKGLVL DLNYFEGADL
     PALDFIGGAI SHFKDAGKPV IAYADNYSQG QYYLASFADE IYLNSIGSVD IHGLSQENLY
     FKEMLDKLAV TPHIFRVGTY KSAVEPFLRN DMSAEAKANM QRWLGEMWNN YVLSVSENRN
     IKKDRILPNA KQYLAELKAL KGNSTAYAQQ RGLVTDVVTR LDLDKKLSAL FGKGSDGKAN
     LIEFDDYLTQ LPDRLEHYNV PNKIAVVNVE GTIIDGESDE ENAGGDTIAR ILRKAHDDNS
     VKAVILRVNS PGGSAFASEI IRQETENLQK IGKPVIVSMG AMAASGGYWI SSTADYIIAD
     SNTITGSIGI FTMFPTFENS IKKIGVHADG VSTTELANTS AFSPLAKPVQ DIYQTEIEHG
     YDRFLEIVSK GRQLSKTQVD KLAQGQVWLG SDAFQNGLVD EIGSFNEAVN KAEQLVNQRQ
     DTAVQDFSVE WFTDDNVSLI STLLSDTKKG AQEQLVKWLG LPAPIQKLQK ELNILTKFND
     PKGQYLYCLN CGKVK