ID   BGAL_BIFLI              Reviewed;         691 AA.
AC   Q93GI5;
DT   03-MAY-2011, integrated into UniProtKB/Swiss-Prot.
DT   01-DEC-2001, sequence version 1.
DT   03-AUG-2022, entry version 57.
DE   RecName: Full=Beta-galactosidase III {ECO:0000312|EMBL:AAL02053.1};
DE            Short=Beta-gal {ECO:0000250|UniProtKB:P19668};
DE            EC=3.2.1.23;
GN   Name=beta-galIII {ECO:0000312|EMBL:AAL02053.1};
OS   Bifidobacterium longum subsp. infantis.
OC   Bacteria; Actinobacteria; Bifidobacteriales; Bifidobacteriaceae;
OC   Bifidobacterium.
OX   NCBI_TaxID=1682;
RN   [1] {ECO:0000305, ECO:0000312|EMBL:AAL02053.1}
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA], FUNCTION, CATALYTIC ACTIVITY, AND
RP   SUBSTRATE SPECIFICITY.
RC   STRAIN=HL96 {ECO:0000312|EMBL:AAL02053.1};
RX   PubMed=11526031; DOI=10.1128/aem.67.9.4256-4263.2001;
RA   Hung M.N., Xia Z., Hu N.T., Lee B.H.;
RT   "Molecular and biochemical analysis of two beta-galactosidases from
RT   Bifidobacterium infantis HL96.";
RL   Appl. Environ. Microbiol. 67:4256-4263(2001).
CC   -!- FUNCTION: Specific for beta-D-anomer-linked galactoside substrates.
CC       Hydrolyzes o-nitrophenyl-beta-D-galactopyranoside (ONPG), chromogen 5-
CC       bromo-4-chloro-3-indolyl-beta-D-galactopyranoside (X-gal) and to a
CC       lesser extent lactose. Hydrolyzes p-nitrophenyl-beta-D-galacturonide
CC       very slightly. Does not hydrolyze maltose, sucrose, raffinose or
CC       melibiose. Has some transgalactosylation activity yielding galacto-
CC       oligosaccharides (GaOS), including O-beta-D-galactopyranosyl-(1,3)-O-
CC       beta-D-galactopyranosyl-(1-4)-D-glucopyranose.
CC       {ECO:0000269|PubMed:11526031}.
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:11526031};
CC   -!- SIMILARITY: Belongs to the glycosyl hydrolase 42 family. {ECO:0000255}.
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DR   EMBL; AF192266; AAL02053.1; -; Genomic_DNA.
DR   AlphaFoldDB; Q93GI5; -.
DR   SMR; Q93GI5; -.
DR   CAZy; GH42; Glycoside Hydrolase Family 42.
DR   GO; GO:0009341; C:beta-galactosidase complex; IEA:InterPro.
DR   GO; GO:0004565; F:beta-galactosidase activity; IEA:UniProtKB-EC.
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.
FT   CHAIN           1..691
FT                   /note="Beta-galactosidase III"
FT                   /id="PRO_0000407685"
FT   ACT_SITE        160
FT                   /note="Proton donor"
FT                   /evidence="ECO:0000250|UniProtKB:O69315"
FT   ACT_SITE        318
FT                   /note="Nucleophile"
FT                   /evidence="ECO:0000250|UniProtKB:O69315"
FT   BINDING         121
FT                   /ligand="substrate"
FT                   /evidence="ECO:0000250|UniProtKB:O69315"
FT   BINDING         159
FT                   /ligand="substrate"
FT                   /evidence="ECO:0000250|UniProtKB:O69315"
FT   BINDING         326
FT                   /ligand="substrate"
FT                   /evidence="ECO:0000250|UniProtKB:O69315"
FT   BINDING         366..369
FT                   /ligand="substrate"
FT                   /evidence="ECO:0000250|UniProtKB:O69315"
SQ   SEQUENCE   691 AA;  77453 MW;  DAC10B3E74607C7F CRC64;
     MEHRAFKWPQ PLAGNKPRIW YVGDYNPDQW PEEVWDEDVA LMQQAGVNLV SVAIFSWAKL
     EPEEGVYDFD WLDRVIDKLG KAGIAVDLAS GTASPPMWMT QAHPEILWVD YRGDVCQPGA
     RQHWRATSPV FLDYALNLCR KMAEHYKDNP YVVSWHVSNE YGCHNRFDYS EDAERAFQKW
     CEKKYGTIDA VNDAWGTAFW AQRMNNFSEI IPPRFIGDGN FMNPGKLLDW KRFSSDALLD
     FYKAERDALL EIAPKPQTTN FMVSAGCTVL DYDKWGHDVD FVSNDHYFSP GEAHFDEMAY
     AACLTDGIAR KNPWFLMEHS TSAVNWRPTN YRLEPGELVR DSLAHLAMGA DAICYFQWRQ
     SKAGAEKWHS AMVPHAGPDS QIFRDVCELG ADLNKLADEG LLSTKLVKSK VAVVFDYESQ
     WATEHTATPT QEVRHWTEPL DWFRALADNG LTADVVPVRG PWDEYEAVVL PSLAILSEQT
     TRRVREYVAN GGKLFVTYYT GLVDDRDHVW LGGYPGSIRD VVGVRVEEFA PMGTDAPGTM
     DHLDLDNGTV AHDFADVITS VADTAHVVAS FKADKWTGFD GAPAITVNDF GDGKAAYVGA
     RLGREGLAKS LPALLEELGI ETSAEDDRGE VVRVERADET GENHFVFLFN RTHDVAVVDV
     EGEPLVASLA QVNESEHTAA IQPNGVLVVK L