ID   BGAL_THETU              Reviewed;         716 AA.
AC   P26257;
DT   01-MAY-1992, integrated into UniProtKB/Swiss-Prot.
DT   01-MAY-1992, sequence version 1.
DT   03-AUG-2022, entry version 92.
DE   RecName: Full=Beta-galactosidase;
DE            Short=Beta-gal;
DE            EC=3.2.1.23;
DE   AltName: Full=Lactase;
GN   Name=lacZ;
OS   Thermoanaerobacterium thermosulfurigenes (Clostridium thermosulfurogenes).
OC   Bacteria; Firmicutes; Clostridia; Thermoanaerobacterales;
OC   Thermoanaerobacterales Family III. Incertae Sedis; Thermoanaerobacterium.
OX   NCBI_TaxID=33950;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA], AND PROTEIN SEQUENCE OF 1-27.
RC   STRAIN=DSM 3896 / EM1;
RX   PubMed=1840542; DOI=10.1016/0378-1119(91)90560-x;
RA   Burchhardt G., Bahl H.;
RT   "Cloning and analysis of the beta-galactosidase-encoding gene from
RT   Clostridium thermosulfurogenes EM1.";
RL   Gene 106:13-19(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   -!- BIOPHYSICOCHEMICAL PROPERTIES:
CC       Temperature dependence:
CC         Thermostable up to 70 degrees Celsius.;
CC   -!- SUBUNIT: Homodimer.
CC   -!- SIMILARITY: Belongs to the glycosyl hydrolase 2 family. {ECO:0000305}.
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DR   EMBL; M57579; AAA23249.1; -; Genomic_DNA.
DR   PIR; JU0275; JU0275.
DR   AlphaFoldDB; P26257; -.
DR   SMR; P26257; -.
DR   CAZy; GH2; Glycoside Hydrolase Family 2.
DR   PRIDE; P26257; -.
DR   GO; GO:0004565; F:beta-galactosidase activity; IEA:UniProtKB-EC.
DR   GO; GO:0016052; P:carbohydrate catabolic process; IEA:UniProt.
DR   Gene3D; 2.60.40.10; -; 2.
DR   InterPro; IPR036156; Beta-gal/glucu_dom_sf.
DR   InterPro; IPR008979; Galactose-bd-like_sf.
DR   InterPro; IPR040605; Glyco_hydro2_dom5.
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; IPR006102; Glyco_hydro_2_Ig-like.
DR   InterPro; IPR006104; Glyco_hydro_2_N.
DR   InterPro; IPR017853; Glycoside_hydrolase_SF.
DR   InterPro; IPR013783; Ig-like_fold.
DR   Pfam; PF18565; Glyco_hydro2_C5; 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   PRINTS; PR00132; GLHYDRLASE2.
DR   SUPFAM; SSF49303; SSF49303; 1.
DR   SUPFAM; SSF49785; SSF49785; 1.
DR   SUPFAM; SSF51445; SSF51445; 1.
DR   PROSITE; PS00719; GLYCOSYL_HYDROL_F2_1; 1.
DR   PROSITE; PS00608; GLYCOSYL_HYDROL_F2_2; 1.
PE   1: Evidence at protein level;
KW   Direct protein sequencing; Glycosidase; Hydrolase.
FT   CHAIN           1..716
FT                   /note="Beta-galactosidase"
FT                   /id="PRO_0000057679"
FT   ACT_SITE        389
FT                   /note="Proton donor"
FT                   /evidence="ECO:0000250"
FT   ACT_SITE        462
FT                   /note="Nucleophile"
FT                   /evidence="ECO:0000250"
SQ   SEQUENCE   716 AA;  83781 MW;  B4665DE22C6F5F40 CRC64;
     MRKIIPINNN WYFKADYEEG YEKVDDLRSF ENVNLPHTNI ELPYNYFDEK MYQIKSCYKY
     PLHISEKYRD KVIYIHFEGV MAYAQVYLNG LYIGEHKGGY TPFDIRIDEV YDWKKELNML
     TVVVDSTERS DIPPKGGQID YLTYGGIYRE VSLGIYDDVF IKNIKVETHG IYDNEKSLNL
     IVHLENLNHQ SGNVKFKVKI NDKNGKEVFY KEFNTYLDAV KDVYSFNIEN LKDIKLWDVD
     NPNLYEIKVG MKINNFSDEY DNKFGFREAV FKPDGFYLNG RKLKLRGLNR HQSYPYVGYA
     MPRRVQEKDA EILKNELHLN IVRTSHYPQS KHFLNKCDEL GLLVFEEIPG WQYIGNSEWK
     KVAEQNLREM ITRDWNHPSI ILWGVRINES QDDDAFYKNM NKIAHEIDPT RQTGGVRYIT
     NSSFLEDVYT FNDFIHDGIN KPLRKQQEVT GLEHNVPYLV TEYNGHMYPT KRFDNEERQM
     EHCLRHLRIQ NASYLDDSIS GAIGWCAFDY NTHKDFGSGD RICYHGVMDM FRLPKFASYV
     YKSQVSPDIE PILEPVTFWA RGERSIGGVI PLIIFTNCDY IELQYGNKTK IDNIYPNRDA
     YKGIPYPPII IDYDIVKPEM IGAWGMVWED LTLKGFYKGN KVIERKFSRE PIPTYLYVVP
     DDTILSATQK DATRIVVKIL DQYGNLLPFI NEVIKIEIEG PAKLQGPNEV ALIGGA