ID   BGAL_CLOAT              Reviewed;         897 AA.
AC   P24131;
DT   01-MAR-1992, integrated into UniProtKB/Swiss-Prot.
DT   01-FEB-1996, sequence version 2.
DT   02-SEP-2026, entry version 105.
DE   RecName: Full=Beta-galactosidase;
DE            Short=Beta-gal;
DE            EC=3.2.1.23;
DE   AltName: Full=Lactase;
GN   Name=cbgA;
OS   Clostridium acetobutylicum.
OC   Bacteria; Bacillati; Bacillota; Clostridia; Eubacteriales; Clostridiaceae;
OC   Clostridium.
OX   NCBI_TaxID=1488;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RC   STRAIN=DSM 1732 / NCIMB 2951 / Weizman;
RX   PubMed=1850729; DOI=10.1128/jb.173.10.3084-3095.1991;
RA   Hancock K.R., Rockman E., Young C.A., Pearce L., Maddox I.S., Scott D.B.;
RT   "Expression and nucleotide sequence of the Clostridium acetobutylicum beta-
RT   galactosidase gene cloned in Escherichia coli.";
RL   J. Bacteriol. 173:3084-3095(1991).
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=Hydrolysis of terminal non-reducing beta-D-galactose residues
CC         in beta-D-galactosides.; EC=3.2.1.23;
CC   -!- INDUCTION: Late in the ABE (acetone, butanol, and ethanol) fermentation
CC       and subject to glucose repression.
CC   -!- SIMILARITY: Belongs to the glycosyl hydrolase 2 family. {ECO:0000305}.
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DR   EMBL; M35107; AAA23216.1; -; Genomic_DNA.
DR   PIR; A39405; A39405.
DR   AlphaFoldDB; P24131; -.
DR   SMR; P24131; -.
DR   CAZy; GH2; Glycoside Hydrolase Family 2.
DR   GO; GO:0009341; C:beta-galactosidase complex; IEA:InterPro.
DR   GO; GO:0004565; F:beta-galactosidase activity; IEA:UniProtKB-EC.
DR   GO; GO:0030246; F:carbohydrate binding; IEA:InterPro.
DR   GO; GO:0005990; P:lactose catabolic process; IEA:TreeGrafter.
DR   Gene3D; 2.70.98.10; -; 1.
DR   Gene3D; 2.60.120.260; Galactose-binding domain-like; 1.
DR   Gene3D; 3.20.20.80; Glycosidases; 1.
DR   Gene3D; 2.60.40.10; Immunoglobulins; 2.
DR   InterPro; IPR004199; B-gal_small/dom_5.
DR   InterPro; IPR050347; Bact_Beta-galactosidase.
DR   InterPro; IPR036156; Beta-gal/glucu_dom_sf.
DR   InterPro; IPR011013; Gal_mutarotase_sf_dom.
DR   InterPro; IPR008979; Galactose-bd-like_sf.
DR   InterPro; IPR014718; GH-type_carb-bd.
DR   InterPro; IPR017853; GH_hydrolase_sf.
DR   InterPro; IPR006101; Glyco_hydro_2.
DR   InterPro; IPR023232; Glyco_hydro_2_AS.
DR   InterPro; IPR006103; Glyco_hydro_2_cat.
DR   InterPro; IPR023230; Glyco_hydro_2_CS.
DR   InterPro; IPR006104; Glyco_hydro_2_N.
DR   InterPro; IPR013783; Ig-like_fold.
DR   InterPro; IPR006102; Ig-like_GH2.
DR   InterPro; IPR032312; LacZ_4.
DR   PANTHER; PTHR46323; BETA-GALACTOSIDASE; 1.
DR   PANTHER; PTHR46323:SF2; BETA-GALACTOSIDASE; 1.
DR   Pfam; PF02929; Bgal_small_N; 1.
DR   Pfam; PF00703; Glyco_hydro_2; 1.
DR   Pfam; PF02836; Glyco_hydro_2_C; 1.
DR   Pfam; PF02837; Glyco_hydro_2_N; 1.
DR   Pfam; PF16353; LacZ_4; 1.
DR   PRINTS; PR00132; GLHYDRLASE2.
DR   SMART; SM01038; Bgal_small_N; 1.
DR   SUPFAM; SSF51445; (Trans)glycosidases; 1.
DR   SUPFAM; SSF49303; beta-Galactosidase/glucuronidase domain; 2.
DR   SUPFAM; SSF74650; Galactose mutarotase-like; 1.
DR   SUPFAM; SSF49785; Galactose-binding domain-like; 1.
DR   PROSITE; PS00719; GLYCOSYL_HYDROL_F2_1; 1.
DR   PROSITE; PS00608; GLYCOSYL_HYDROL_F2_2; 1.
PE   2: Evidence at transcript level;
KW   Glycosidase; Hydrolase.
FT   CHAIN           1..897
FT                   /note="Beta-galactosidase"
FT                   /id="PRO_0000057660"
FT   ACT_SITE        459
FT                   /note="Proton donor"
FT                   /evidence="ECO:0000250|UniProtKB:P00722"
FT   ACT_SITE        525
FT                   /note="Nucleophile"
FT                   /evidence="ECO:0000250|UniProtKB:P00722"
SQ   SEQUENCE   897 AA;  105020 MW;  E13DB8674992A32F CRC64;
     MINNKPSLDW LENPEIFRVN RIDAHSDTWF YEKFEDVKLE DTMPLKQNLN GKWRFSYSEN
     SSLRIKEFYK DEFDVSWIDY IEVPGHIQLQ GYDKCQYINT MYPWEGHDEL RPPHISKTYN
     PVGSYVTFFE VKDELKNKQT FISFQGVETA FYVWVNGEFV GYSEDTFTPS EFDITDYLRE
     GENKLAVEVY KRSSASWIED QDFWRFSGIF RDVYLYAVPE THVNDIFIKT DLYDDFKNAK
     LNAELKMIGN SETTVETYLE DKEGNKIAIS EKIPFSDELT LYLDAQNINL WSAEEPNLYT
     LYILVNKKDG NLIEVVTQKI GFRHFEMKDK IMCLKWKRII FKGVNRHEFS ARRGRSITKE
     DMLWDIKFLK QHNINAVRTS HYPNQSLWYR LCDEYGIYLI DETNLESHGS WQKMGQIEPS
     WNVPGSLPQW QAAVLDRASS MVERDKNHPS VLIWSCGNES YAGEDIYQMS KYFRKKDPSR
     LVHYEGVTRC REFMTRRHES RMYAKAAEIE EYLNDNPKKP YISCEYMHSM GNSTGGMMKY
     TELEDKYLMY QGGFIWDYGD QALYRKLPDG KEVLAYGGDF TDRPTDYNFS GNGLIYADRT
     ISPKAQEVKY LYQNVKLEPD EKGVTIKNQN LFVNTDKYDL YYIVERDGKL IKDGYLNVSV
     APDEEKYIEL PIGNYNFPEE IVLTTSLRLA QATLWAEKGY EIAFGQKVIK EKSDMNNHNS
     ESKMKIIHGD VNIGVHGKDF KAIFSKQEGG IVSLRYNNKE FITRTPKTFY WRATTDNDRG
     NRHEFRCSQW LAATMGQKYV DFSVEEFDEK ITLYYTYQLP TVPSTNVKIT YEVSGEGIIK
     VNVKYKGVSG LPELPVLGMD FKLLAEFNSF SWYGMGPEEN YIDRCEGAKL GIYESTQ
//