ID   LEP_BUCBP               Reviewed;         310 AA.
AC   Q89AM6;
DT   13-APR-2004, integrated into UniProtKB/Swiss-Prot.
DT   01-JUN-2003, sequence version 1.
DT   04-NOV-2026, entry version 133.
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=bbp_240;
OS   Buchnera aphidicola subsp. Baizongia pistaciae (strain Bp).
OC   Bacteria; Pseudomonadati; Pseudomonadota; Gammaproteobacteria;
OC   Enterobacterales; Erwiniaceae; Buchnera.
OX   NCBI_TaxID=224915;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=Bp;
RX   PubMed=12522265; DOI=10.1073/pnas.0235981100;
RA   van Ham R.C.H.J., Kamerbeek J., Palacios C., Rausell C., Abascal F.,
RA   Bastolla U., Fernandez J.M., Jimenez L., Postigo M., Silva F.J.,
RA   Tamames J., Viguera E., Latorre A., Valencia A., Moran F., Moya A.;
RT   "Reductive genome evolution in Buchnera aphidicola.";
RL   Proc. Natl. Acad. Sci. U.S.A. 100:581-586(2003).
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; AE016826; AAO26967.1; -; Genomic_DNA.
DR   RefSeq; WP_011091368.1; NC_004545.1.
DR   AlphaFoldDB; Q89AM6; -.
DR   SMR; Q89AM6; -.
DR   STRING; 224915.bbp_240; -.
DR   MEROPS; S26.001; -.
DR   KEGG; bab:bbp_240; -.
DR   eggNOG; COG0681; Bacteria.
DR   HOGENOM; CLU_028723_1_1_6; -.
DR   OMA; AACWDSK; -.
DR   OrthoDB; 9815782at2; -.
DR   Proteomes; UP000000601; Chromosome.
DR   GO; GO:0005886; C:plasma membrane; IEA:UniProtKB-SubCell.
DR   GO; GO:0004252; F:serine-type endopeptidase activity; IEA:InterPro.
DR   GO; GO:0009003; F:signal peptidase activity; IEA:UniProtKB-EC.
DR   GO; GO:0051604; P:protein maturation; IEA:InterPro.
DR   GO; GO:0006508; P:proteolysis; IEA:InterPro.
DR   CDD; cd06530; S26_SPase_I; 1.
DR   Gene3D; 2.170.230.10; -; 1.
DR   Gene3D; 2.10.109.10; Umud Fragment, subunit A; 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   NCBIfam; NF008114; lepB; 1.
DR   NCBIfam; TIGR02227; sigpep_I_bact; 1.
DR   PANTHER; PTHR43390:SF1; CHLOROPLAST PROCESSING PEPTIDASE; 1.
DR   PANTHER; PTHR43390; SIGNAL PEPTIDASE I; 1.
DR   Pfam; PF10502; Peptidase_S26; 1.
DR   PRINTS; PR00727; LEADERPTASE.
DR   SUPFAM; SSF51306; LexA/Signal peptidase; 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; Reference proteome;
KW   Transmembrane; Transmembrane helix.
FT   CHAIN           1..310
FT                   /note="Signal peptidase I"
FT                   /id="PRO_0000109505"
FT   TRANSMEM        5..25
FT                   /note="Helical"
FT                   /evidence="ECO:0000255"
FT   TOPO_DOM        26..57
FT                   /note="Cytoplasmic"
FT                   /evidence="ECO:0000255"
FT   TRANSMEM        58..78
FT                   /note="Helical"
FT                   /evidence="ECO:0000255"
FT   TOPO_DOM        79..310
FT                   /note="Extracellular"
FT                   /evidence="ECO:0000255"
FT   ACT_SITE        82
FT                   /evidence="ECO:0000250"
FT   ACT_SITE        137
FT                   /evidence="ECO:0000250"
SQ   SEQUENCE   310 AA;  36313 MW;  6CB12207E9CF21B8 CRC64;
     MSNYLSSFLL ASSLITGTLW IINKILSHNL LDSKIPFNIK KSKIYYKSKQ VVQTFASFFP
     ILIIVFIIRT FICEPFQIPS ESMMPTLLPG DFILVKKFSY GIKNPFSNNV IVFINTPKRG
     DIVVFKHPNN NAINYVKRIV GLPGDKINYN ILTKRLTITP NNINEQHTKN ISINYKYIKP
     NDFTKHFKLN NIILNNVHSL ESSNNNLLQL EMYQEKIEKI AYNIFFKKKL IDQKDLYFKQ
     FSQKQGTWIV PKHKYFVLGD NRDNSLDSRY WGFVPEKNLI GKVVFIWMHL IKKEGQWPTG
     IQFDRIGNIY
//