ID   BGAL2_LACAI             Reviewed;         667 AA.
AC   C6H178;
DT   03-MAY-2011, integrated into UniProtKB/Swiss-Prot.
DT   01-SEP-2009, sequence version 1.
DT   03-AUG-2022, entry version 35.
DE   RecName: Full=Beta-galactosidase LacA;
DE            Short=Beta-gal {ECO:0000250|UniProtKB:Q5FJ41};
DE            EC=3.2.1.23;
GN   Name=lacA {ECO:0000312|EMBL:CAZ66938.1};
OS   Lactobacillus acidophilus.
OC   Bacteria; Firmicutes; Bacilli; Lactobacillales; Lactobacillaceae;
OC   Lactobacillus.
OX   NCBI_TaxID=1579;
RN   [1] {ECO:0000305, ECO:0000312|EMBL:CAZ66938.1}
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA], FUNCTION, CATALYTIC ACTIVITY,
RP   BIOPHYSICOCHEMICAL PROPERTIES, AND SUBSTRATE SPECIFICITY.
RC   STRAIN=FUA3191 {ECO:0000312|EMBL:CAZ66938.1};
RX   PubMed=20822875; DOI=10.1016/j.syapm.2010.07.002;
RA   Schwab C., Soerensen K.I., Gaenzle M.G.;
RT   "Heterologous expression of glycoside hydrolase family 2 and 42 beta-
RT   galactosidases of lactic acid bacteria in Lactococcus lactis.";
RL   Syst. Appl. Microbiol. 33:300-307(2010).
CC   -!- FUNCTION: Hydrolyzes lactose, oNP-galactoside (oNPG), pNP-galactosidase
CC       (pNPG), pNP-mannoside, pNP-glucoside, pNP-fucoside, pNP-N-
CC       acetylglucosamide, but not pNP-arabinoside or 4-methylumbelliferyl-
CC       beta-galactopyranoside (MUG). Transgalactosylates lactose at 10 g/L,
CC       but not at 270 g/L. {ECO:0000269|PubMed:20822875}.
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         Evidence={ECO:0000269|PubMed:20822875};
CC   -!- BIOPHYSICOCHEMICAL PROPERTIES:
CC       pH dependence:
CC         Hydrolyzes lactose at pH 6.5, 6.8 and 7.2.
CC         {ECO:0000269|PubMed:20822875};
CC       Temperature dependence:
CC         Hydrolyzes lactose between 30-45 degrees Celsius.
CC         {ECO:0000269|PubMed:20822875};
CC   -!- SIMILARITY: Belongs to the glycosyl hydrolase 42 family. {ECO:0000255}.
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DR   EMBL; FN424352; CAZ66938.1; -; Genomic_DNA.
DR   AlphaFoldDB; C6H178; -.
DR   SMR; C6H178; -.
DR   CAZy; GH42; Glycoside Hydrolase Family 42.
DR   PRIDE; C6H178; -.
DR   GO; GO:0009341; C:beta-galactosidase complex; IEA:InterPro.
DR   GO; GO:0004565; F:beta-galactosidase activity; IEA:UniProtKB-EC.
DR   GO; GO:0046872; F:metal ion binding; IEA:UniProtKB-KW.
DR   GO; GO:0006012; P:galactose metabolic process; IEA:InterPro.
DR   Gene3D; 2.60.40.1180; -; 1.
DR   Gene3D; 3.40.50.880; -; 1.
DR   InterPro; IPR013739; Beta_galactosidase_C.
DR   InterPro; IPR013738; Beta_galactosidase_Trimer.
DR   InterPro; IPR029062; Class_I_gatase-like.
DR   InterPro; IPR003476; Glyco_hydro_42.
DR   InterPro; IPR013529; Glyco_hydro_42_N.
DR   InterPro; IPR013780; Glyco_hydro_b.
DR   InterPro; IPR017853; Glycoside_hydrolase_SF.
DR   PANTHER; PTHR36447; PTHR36447; 1.
DR   Pfam; PF02449; Glyco_hydro_42; 1.
DR   Pfam; PF08533; Glyco_hydro_42C; 1.
DR   Pfam; PF08532; Glyco_hydro_42M; 1.
DR   PIRSF; PIRSF001084; B-galactosidase; 1.
DR   SUPFAM; SSF51445; SSF51445; 1.
DR   SUPFAM; SSF52317; SSF52317; 1.
PE   1: Evidence at protein level;
KW   Glycosidase; Hydrolase; Metal-binding; Zinc.
FT   CHAIN           1..667
FT                   /note="Beta-galactosidase LacA"
FT                   /id="PRO_0000407691"
FT   ACT_SITE        148
FT                   /note="Proton donor"
FT                   /evidence="ECO:0000250|UniProtKB:O69315"
FT   ACT_SITE        307
FT                   /note="Nucleophile"
FT                   /evidence="ECO:0000250|UniProtKB:O69315"
FT   BINDING         109
FT                   /ligand="substrate"
FT                   /evidence="ECO:0000250|UniProtKB:O69315"
FT   BINDING         113
FT                   /ligand="Zn(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29105"
FT                   /evidence="ECO:0000250|UniProtKB:O69315"
FT   BINDING         147
FT                   /ligand="substrate"
FT                   /evidence="ECO:0000250|UniProtKB:O69315"
FT   BINDING         153
FT                   /ligand="Zn(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29105"
FT                   /evidence="ECO:0000250|UniProtKB:O69315"
FT   BINDING         155
FT                   /ligand="Zn(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29105"
FT                   /evidence="ECO:0000250|UniProtKB:O69315"
FT   BINDING         158
FT                   /ligand="Zn(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29105"
FT                   /evidence="ECO:0000250|UniProtKB:O69315"
FT   BINDING         315
FT                   /ligand="substrate"
FT                   /evidence="ECO:0000250|UniProtKB:O69315"
FT   BINDING         355..358
FT                   /ligand="substrate"
FT                   /evidence="ECO:0000250|UniProtKB:O69315"
SQ   SEQUENCE   667 AA;  76705 MW;  C42D4FE9EE44BBD4 CRC64;
     MTQLSRFLYG GDYNPDQWPE ETWSKDIHVF KKADINSATI NIFSWALLEP REGKYNFSKL
     DKVVQQLSDA NFDIVMGTAT AAMPAWMFKK YPDIARVDYQ DRRHVFGQRH NFCPNSSNYQ
     RLAGELEKQL VERYKDNKHI VFWHINNEYG GNCYCENCQN AFKKWLKNKY KTVEGLNKAW
     NMNVWSHTIY DWDEIVVPNE LGDVWGIKGS ETIVAGLSID YLRFQSESMQ NLFKMEKKII
     KKFDPETPVT TNFHGLPNKM VDYQKWAKGQ DIISYDSYPT YDAPAYKAAF LYDLMRSLKH
     QPFMLMESAP SQVNWQPYSP LKRPGQMEAT EFQAVAHGAD TVQFFRLKQA VGGSEKFHSA
     VIAHSQRTVT RVFKELADLG KKLKNAGPTI LGSKTKARFA IVFDWSNFWS YEYVDGITQD
     LNYVDSILDY YRQFYERNIP TDIIGVDDDF SNYDLVVAPV LYMVKHGLDK KINDYVENGG
     NFVTTYMSGM VNSSDNVYLG GYPGPLKEVT GIWVEESDAV VPGQKIKVLM NGKDYDTGLI
     CNLIHPNDAK ILATYASEFY AGTPAVTENQ YGKGRAWYIG TRLEHQGLTQ LFNHIIFETG
     VESLVCDSHK LEITKRVTED GKELYFVLNM SNEERTLPSK FTGYEDILTG EKAHKDMKGW
     DVQVLRN