BGAL_THETH
ID BGAL_THETH Reviewed; 645 AA.
AC O69315;
DT 24-MAR-2009, integrated into UniProtKB/Swiss-Prot.
DT 01-AUG-1998, sequence version 1.
DT 03-AUG-2022, entry version 82.
DE RecName: Full=Beta-galactosidase;
DE Short=Beta-gal;
DE EC=3.2.1.23;
DE AltName: Full=Lactase;
OS Thermus thermophilus.
OC Bacteria; Deinococcus-Thermus; Deinococci; Thermales; Thermaceae; Thermus.
OX NCBI_TaxID=274;
RN [1]
RP NUCLEOTIDE SEQUENCE [GENOMIC DNA], PROTEIN SEQUENCE OF 1-15,
RP BIOPHYSICOCHEMICAL PROPERTIES, ACTIVITY REGULATION, AND SUBUNIT.
RC STRAIN=A4;
RX PubMed=9757561; DOI=10.1271/bbb.62.1539;
RA Ohtsu N., Motoshima H., Goto K., Tsukasaki F., Matsuzawa H.;
RT "Thermostable beta-galactosidase from an extreme thermophile, Thermus sp.
RT A4: enzyme purification and characterization, and gene cloning and
RT sequencing.";
RL Biosci. Biotechnol. Biochem. 62:1539-1545(1998).
RN [2]
RP X-RAY CRYSTALLOGRAPHY (1.6 ANGSTROMS) IN COMPLEX WITH ZINC ION AND
RP SUBSTRATE, REACTION MECHANISM, AND SUBUNIT.
RX PubMed=12215416; DOI=10.1016/s0022-2836(02)00746-5;
RA Hidaka M., Fushinobu S., Ohtsu N., Motoshima H., Matsuzawa H., Shoun H.,
RA Wakagi T.;
RT "Trimeric crystal structure of the glycoside hydrolase family 42 beta-
RT galactosidase from Thermus thermophilus A4 and the structure of its complex
RT with galactose.";
RL J. Mol. Biol. 322:79-91(2002).
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 -!- ACTIVITY REGULATION: Inhibited by Cu(2+) and Fe(2+), and moderately
CC activated by divalent cations such as Co(2+), Mn(2+) and Zn(2+).
CC Considerably activated by dithiothreitol, beta-mercaptoethanol and
CC cysteine. {ECO:0000269|PubMed:9757561}.
CC -!- BIOPHYSICOCHEMICAL PROPERTIES:
CC Kinetic parameters:
CC KM=19 mM for lactose (at pH 6.5 and at 70 degrees Celsius)
CC {ECO:0000269|PubMed:9757561};
CC KM=5.9 mM for o-nitrophenyl beta-D-galactopyranoside (at pH 6.5 and
CC at 70 degrees Celsius) {ECO:0000269|PubMed:9757561};
CC pH dependence:
CC Optimum pH is 6.5. No activity is detected at pH below 4.5.
CC {ECO:0000269|PubMed:9757561};
CC Temperature dependence:
CC Optimum temperature is 70 degrees Celsius. It retains more than 75%
CC of activity after incubation at 85 degrees Celsius and the half-life
CC at 90 degrees Celsius is 1 hour. Thermostable.
CC {ECO:0000269|PubMed:9757561};
CC -!- SUBUNIT: Homotrimer. {ECO:0000269|PubMed:12215416,
CC ECO:0000269|PubMed:9757561}.
CC -!- MISCELLANEOUS: The trimeric structure is essential to exhibit high
CC enzymatic activity.
CC -!- SIMILARITY: Belongs to the glycosyl hydrolase 42 family. {ECO:0000305}.
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DR EMBL; D85027; BAA28362.1; -; Genomic_DNA.
DR PDB; 1KWG; X-ray; 1.60 A; A=1-645.
DR PDB; 1KWK; X-ray; 2.20 A; A=1-645.
DR PDBsum; 1KWG; -.
DR PDBsum; 1KWK; -.
DR AlphaFoldDB; O69315; -.
DR SMR; O69315; -.
DR CAZy; GH42; Glycoside Hydrolase Family 42.
DR EvolutionaryTrace; O69315; -.
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 3D-structure; Direct protein sequencing; Glycosidase; Hydrolase;
KW Metal-binding; Zinc.
FT CHAIN 1..645
FT /note="Beta-galactosidase"
FT /id="PRO_0000367028"
FT ACT_SITE 141
FT /note="Proton donor"
FT ACT_SITE 312
FT /note="Nucleophile"
FT BINDING 102
FT /ligand="substrate"
FT /evidence="ECO:0000269|PubMed:12215416"
FT BINDING 106
FT /ligand="Zn(2+)"
FT /ligand_id="ChEBI:CHEBI:29105"
FT BINDING 140
FT /ligand="substrate"
FT /evidence="ECO:0000269|PubMed:12215416"
FT BINDING 150
FT /ligand="Zn(2+)"
FT /ligand_id="ChEBI:CHEBI:29105"
FT BINDING 152
FT /ligand="Zn(2+)"
FT /ligand_id="ChEBI:CHEBI:29105"
FT BINDING 155
FT /ligand="Zn(2+)"
FT /ligand_id="ChEBI:CHEBI:29105"
FT BINDING 320
FT /ligand="substrate"
FT /evidence="ECO:0000269|PubMed:12215416"
FT BINDING 360..363
FT /ligand="substrate"
FT STRAND 2..5
FT /evidence="ECO:0007829|PDB:1KWG"
FT HELIX 8..10
FT /evidence="ECO:0007829|PDB:1KWG"
FT HELIX 13..15
FT /evidence="ECO:0007829|PDB:1KWG"
FT HELIX 16..26
FT /evidence="ECO:0007829|PDB:1KWG"
FT STRAND 30..33
FT /evidence="ECO:0007829|PDB:1KWG"
FT HELIX 38..41
FT /evidence="ECO:0007829|PDB:1KWG"
FT HELIX 51..61
FT /evidence="ECO:0007829|PDB:1KWG"
FT TURN 62..64
FT /evidence="ECO:0007829|PDB:1KWG"
FT STRAND 66..70
FT /evidence="ECO:0007829|PDB:1KWG"
FT HELIX 78..83
FT /evidence="ECO:0007829|PDB:1KWG"
FT HELIX 85..87
FT /evidence="ECO:0007829|PDB:1KWG"
FT STRAND 99..102
FT /evidence="ECO:0007829|PDB:1KWG"
FT HELIX 110..127
FT /evidence="ECO:0007829|PDB:1KWG"
FT STRAND 133..137
FT /evidence="ECO:0007829|PDB:1KWG"
FT STRAND 139..141
FT /evidence="ECO:0007829|PDB:1KWG"
FT TURN 142..146
FT /evidence="ECO:0007829|PDB:1KWG"
FT HELIX 153..167
FT /evidence="ECO:0007829|PDB:1KWG"
FT HELIX 170..177
FT /evidence="ECO:0007829|PDB:1KWG"
FT TURN 178..180
FT /evidence="ECO:0007829|PDB:1KWG"
FT HELIX 181..183
FT /evidence="ECO:0007829|PDB:1KWG"
FT HELIX 189..191
FT /evidence="ECO:0007829|PDB:1KWG"
FT HELIX 204..232
FT /evidence="ECO:0007829|PDB:1KWG"
FT STRAND 237..239
FT /evidence="ECO:0007829|PDB:1KWG"
FT HELIX 251..254
FT /evidence="ECO:0007829|PDB:1KWG"
FT HELIX 255..257
FT /evidence="ECO:0007829|PDB:1KWG"
FT STRAND 258..265
FT /evidence="ECO:0007829|PDB:1KWG"
FT HELIX 267..273
FT /evidence="ECO:0007829|PDB:1KWG"
FT HELIX 278..283
FT /evidence="ECO:0007829|PDB:1KWG"
FT TURN 284..287
FT /evidence="ECO:0007829|PDB:1KWG"
FT HELIX 292..303
FT /evidence="ECO:0007829|PDB:1KWG"
FT TURN 304..306
FT /evidence="ECO:0007829|PDB:1KWG"
FT STRAND 308..313
FT /evidence="ECO:0007829|PDB:1KWG"
FT STRAND 319..323
FT /evidence="ECO:0007829|PDB:1KWG"
FT HELIX 331..341
FT /evidence="ECO:0007829|PDB:1KWG"
FT STRAND 347..350
FT /evidence="ECO:0007829|PDB:1KWG"
FT STRAND 356..358
FT /evidence="ECO:0007829|PDB:1KWG"
FT TURN 359..362
FT /evidence="ECO:0007829|PDB:1KWG"
FT HELIX 375..388
FT /evidence="ECO:0007829|PDB:1KWG"
FT STRAND 399..403
FT /evidence="ECO:0007829|PDB:1KWG"
FT HELIX 406..414
FT /evidence="ECO:0007829|PDB:1KWG"
FT HELIX 423..435
FT /evidence="ECO:0007829|PDB:1KWG"
FT TURN 436..438
FT /evidence="ECO:0007829|PDB:1KWG"
FT STRAND 441..444
FT /evidence="ECO:0007829|PDB:1KWG"
FT STRAND 454..459
FT /evidence="ECO:0007829|PDB:1KWG"
FT HELIX 466..473
FT /evidence="ECO:0007829|PDB:1KWG"
FT STRAND 479..481
FT /evidence="ECO:0007829|PDB:1KWG"
FT TURN 483..486
FT /evidence="ECO:0007829|PDB:1KWG"
FT HELIX 501..505
FT /evidence="ECO:0007829|PDB:1KWG"
FT STRAND 510..516
FT /evidence="ECO:0007829|PDB:1KWG"
FT STRAND 523..527
FT /evidence="ECO:0007829|PDB:1KWG"
FT STRAND 530..534
FT /evidence="ECO:0007829|PDB:1KWG"
FT STRAND 536..542
FT /evidence="ECO:0007829|PDB:1KWG"
FT STRAND 548..551
FT /evidence="ECO:0007829|PDB:1KWG"
FT STRAND 556..561
FT /evidence="ECO:0007829|PDB:1KWG"
FT STRAND 564..567
FT /evidence="ECO:0007829|PDB:1KWG"
FT HELIX 573..586
FT /evidence="ECO:0007829|PDB:1KWG"
FT STRAND 598..603
FT /evidence="ECO:0007829|PDB:1KWG"
FT STRAND 606..611
FT /evidence="ECO:0007829|PDB:1KWG"
FT STRAND 613..615
FT /evidence="ECO:0007829|PDB:1KWG"
FT STRAND 626..630
FT /evidence="ECO:0007829|PDB:1KWG"
FT STRAND 632..634
FT /evidence="ECO:0007829|PDB:1KWG"
FT STRAND 638..643
FT /evidence="ECO:0007829|PDB:1KWG"
SQ SEQUENCE 645 AA; 72824 MW; 60FAE1EC1923C6C8 CRC64;
MLGVCYYPEH WPKERWKEDA RRMREAGLSH VRIGEFAWAL LEPEPGRLEW GWLDEAIATL
AAEGLKVVLG TPTATPPKWL VDRYPEILPV DREGRRRRFG GRRHYCFSSP VYREEARRIV
TLLAERYGGL EAVAGFQTDN EYGCHDTVRC YCPRCQEAFR GWLEARYGTI EALNEAWGTA
FWSQRYRSFA EVELPHLTVA EPNPSHLLDY YRFASDQVRA FNRLQVEILR AHAPGKFVTH
NFMGFFTDLD AFALAQDLDF ASWDSYPLGF TDLMPLPPEE KLRYARTGHP DVAAFHHDLY
RGVGRGRFWV MEQQPGPVNW APHNPSPAPG MVRLWTWEAL AHGAEVVSYF RWRQAPFAQE
QMHAGLHRPD SAPDQGFFEA KRVAEELAAL ALPPVAQAPV ALVFDYEAAW IYEVQPQGAE
WSYLGLVYLF YSALRRLGLD VDVVPPGASL RGYAFAVVPS LPIVREEALE AFREAEGPVL
FGPRSGSKTE TFQIPKELPP GPLQALLPLK VVRVESLPPG LLEVAEGALG RFPLGLWREW
VEAPLKPLLT FQDGKGALYR EGRYLYLAAW PSPELAGRLL SALAAEAGLK VLSLPEGLRL
RRRGTWVFAF NYGPEAVEAP ASEGARFLLG SRRVGPYDLA VWEEA
