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 28-JUN-2023, entry version 85. DE RecName: Full=Beta-galactosidase; DE Short=Beta-gal; DE EC=3.2.1.23; DE AltName: Full=Lactase; OS Thermus thermophilus. OC Bacteria; Deinococcota; 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}. CC --------------------------------------------------------------------------- CC Copyrighted by the UniProt Consortium, see https://www.uniprot.org/terms CC Distributed under the Creative Commons Attribution (CC BY 4.0) License CC --------------------------------------------------------------------------- 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 CDD; cd03143; A4_beta-galactosidase_middle_domain; 1. DR Gene3D; 3.40.50.880; -; 1. DR Gene3D; 3.20.20.80; Glycosidases; 1. DR Gene3D; 2.60.40.1180; Golgi alpha-mannosidase II; 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; BETA-GALACTOSIDASE GANA; 1. DR PANTHER; PTHR36447:SF2; BETA-GALACTOSIDASE YESZ; 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; (Trans)glycosidases; 1. DR SUPFAM; SSF52317; Class I glutamine amidotransferase-like; 1. DR SUPFAM; SSF51011; Glycosyl hydrolase domain; 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 //