ID   LEP_BUCAP               Reviewed;         312 AA.
AC   Q8K9R0;
DT   08-NOV-2002, integrated into UniProtKB/Swiss-Prot.
DT   01-OCT-2002, sequence version 1.
DT   03-AUG-2022, entry version 125.
DE   RecName: Full=Signal peptidase I;
DE            Short=SPase I;
DE            EC=3.4.21.89;
DE   AltName: Full=Leader peptidase I;
GN   Name=lepB; OrderedLocusNames=BUsg_250;
OS   Buchnera aphidicola subsp. Schizaphis graminum (strain Sg).
OC   Bacteria; Proteobacteria; Gammaproteobacteria; Enterobacterales;
OC   Erwiniaceae; Buchnera.
OX   NCBI_TaxID=198804;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=Sg;
RX   PubMed=12089438; DOI=10.1126/science.1071278;
RA   Tamas I., Klasson L., Canbaeck B., Naeslund A.K., Eriksson A.-S.,
RA   Wernegreen J.J., Sandstroem J.P., Moran N.A., Andersson S.G.E.;
RT   "50 million years of genomic stasis in endosymbiotic bacteria.";
RL   Science 296:2376-2379(2002).
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=Cleavage of hydrophobic, N-terminal signal or leader sequences
CC         from secreted and periplasmic proteins.; EC=3.4.21.89;
CC   -!- SUBCELLULAR LOCATION: Cell membrane {ECO:0000250}; Multi-pass membrane
CC       protein {ECO:0000250}.
CC   -!- SIMILARITY: Belongs to the peptidase S26 family. {ECO:0000305}.
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DR   EMBL; AE013218; AAM67809.1; -; Genomic_DNA.
DR   RefSeq; WP_011053776.1; NC_004061.1.
DR   AlphaFoldDB; Q8K9R0; -.
DR   SMR; Q8K9R0; -.
DR   STRING; 198804.BUsg_250; -.
DR   MEROPS; S26.001; -.
DR   EnsemblBacteria; AAM67809; AAM67809; BUsg_250.
DR   KEGG; bas:BUsg_250; -.
DR   eggNOG; COG0681; Bacteria.
DR   HOGENOM; CLU_028723_1_1_6; -.
DR   OMA; SDSRFWG; -.
DR   OrthoDB; 1741894at2; -.
DR   Proteomes; UP000000416; 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:0004252; F:serine-type endopeptidase activity; IEA:UniProtKB-EC.
DR   GO; GO:0006465; P:signal peptide processing; IEA:InterPro.
DR   CDD; cd06530; S26_SPase_I; 1.
DR   Gene3D; 2.170.230.10; -; 1.
DR   InterPro; IPR036286; LexA/Signal_pep-like_sf.
DR   InterPro; IPR000223; Pept_S26A_signal_pept_1.
DR   InterPro; IPR019758; Pept_S26A_signal_pept_1_CS.
DR   InterPro; IPR019757; Pept_S26A_signal_pept_1_Lys-AS.
DR   InterPro; IPR019756; Pept_S26A_signal_pept_1_Ser-AS.
DR   InterPro; IPR019533; Peptidase_S26.
DR   InterPro; IPR019766; Sign_pep_all-beta_subdom.
DR   PANTHER; PTHR43390; PTHR43390; 1.
DR   Pfam; PF10502; Peptidase_S26; 1.
DR   PRINTS; PR00727; LEADERPTASE.
DR   SUPFAM; SSF51306; SSF51306; 1.
DR   TIGRFAMs; TIGR02227; sigpep_I_bact; 1.
DR   PROSITE; PS00501; SPASE_I_1; 1.
DR   PROSITE; PS00760; SPASE_I_2; 1.
DR   PROSITE; PS00761; SPASE_I_3; 1.
PE   3: Inferred from homology;
KW   Cell membrane; Hydrolase; Membrane; Protease; Transmembrane;
KW   Transmembrane helix.
FT   CHAIN           1..312
FT                   /note="Signal peptidase I"
FT                   /id="PRO_0000109504"
FT   TRANSMEM        7..27
FT                   /note="Helical"
FT                   /evidence="ECO:0000255"
FT   TOPO_DOM        28..63
FT                   /note="Cytoplasmic"
FT                   /evidence="ECO:0000255"
FT   TRANSMEM        64..84
FT                   /note="Helical"
FT                   /evidence="ECO:0000255"
FT   TOPO_DOM        85..312
FT                   /note="Extracellular"
FT                   /evidence="ECO:0000255"
FT   ACT_SITE        88
FT                   /evidence="ECO:0000250"
FT   ACT_SITE        142
FT                   /evidence="ECO:0000250"
SQ   SEQUENCE   312 AA;  37103 MW;  63602053A16A0D8B CRC64;
     MRNILTIFLL TSTFFTGILW IIDHILLIKN YFYNKKKTKN NNTILINKVI LENKKCFFRS
     LSSLFPTFFI VFIIRSFIYE PFQIPSGSMM PTLLIGDFIL VKKFSYGIKE PITNKTIIKM
     NLPQRGDIVV FKHPKNNIDY IKRVVGLPGD KIQYDINRKK IKICINYTNQ KNCENKLFIT
     YSKPKLSNFF QKIYLLKSRT NEEEKVYNSI YFKKVEEKIN NLKHNILILD GINSKINDYY
     QQKGMPKLIW IVPKNKYFMM GDNRDNSLDS RYWGFVPEEN LLGKATKIWM SFEKKENEWP
     TGIRIKRIGN IY