ID LACI_ECOLI Reviewed; 360 AA. AC P03023; O09196; P71309; Q2MC79; Q47338; DT 21-JUL-1986, integrated into UniProtKB/Swiss-Prot. DT 19-JUL-2003, sequence version 3. DT 27-MAR-2024, entry version 206. DE RecName: Full=Lactose operon repressor; GN Name=lacI; OrderedLocusNames=b0345, JW0336; OS Escherichia coli (strain K12). OC Bacteria; Pseudomonadota; Gammaproteobacteria; Enterobacterales; OC Enterobacteriaceae; Escherichia. OX NCBI_TaxID=83333; RN [1] RP NUCLEOTIDE SEQUENCE [GENOMIC DNA]. RX PubMed=355891; DOI=10.1038/274765a0; RA Farabaugh P.J.; RT "Sequence of the lacI gene."; RL Nature 274:765-769(1978). RN [2] RP NUCLEOTIDE SEQUENCE [GENOMIC DNA]. RA Chen J., Matthews K.K.S.M.; RL Submitted (MAY-1991) to the EMBL/GenBank/DDBJ databases. RN [3] RP NUCLEOTIDE SEQUENCE [GENOMIC DNA]. RA Marsh S.; RL Submitted (JAN-1997) to the EMBL/GenBank/DDBJ databases. RN [4] RP NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA]. RC STRAIN=K12 / MG1655 / ATCC 47076; RA Chung E., Allen E., Araujo R., Aparicio A.M., Davis K., Duncan M., RA Federspiel N., Hyman R., Kalman S., Komp C., Kurdi O., Lew H., Lin D., RA Namath A., Oefner P., Roberts D., Schramm S., Davis R.W.; RT "Sequence of minutes 4-25 of Escherichia coli."; RL Submitted (JAN-1997) to the EMBL/GenBank/DDBJ databases. RN [5] RP NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA]. RC STRAIN=K12 / MG1655 / ATCC 47076; RX PubMed=9278503; DOI=10.1126/science.277.5331.1453; RA Blattner F.R., Plunkett G. III, Bloch C.A., Perna N.T., Burland V., RA Riley M., Collado-Vides J., Glasner J.D., Rode C.K., Mayhew G.F., RA Gregor J., Davis N.W., Kirkpatrick H.A., Goeden M.A., Rose D.J., Mau B., RA Shao Y.; RT "The complete genome sequence of Escherichia coli K-12."; RL Science 277:1453-1462(1997). RN [6] RP NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA]. RC STRAIN=K12 / W3110 / ATCC 27325 / DSM 5911; RX PubMed=16738553; DOI=10.1038/msb4100049; RA Hayashi K., Morooka N., Yamamoto Y., Fujita K., Isono K., Choi S., RA Ohtsubo E., Baba T., Wanner B.L., Mori H., Horiuchi T.; RT "Highly accurate genome sequences of Escherichia coli K-12 strains MG1655 RT and W3110."; RL Mol. Syst. Biol. 2:E1-E5(2006). RN [7] RP PROTEIN SEQUENCE OF 1-147; 159-230 AND 233-360. RX PubMed=1107032; DOI=10.1111/j.1432-1033.1975.tb02477.x; RA Beyreuther K., Adler K., Fanning E., Murray C., Klemm A., Geisler N.; RT "Amino-acid sequence of lac repressor from Escherichia coli. Isolation, RT sequence analysis and sequence assembly of tryptic peptides and cyanogen- RT bromide fragments."; RL Eur. J. Biochem. 59:491-509(1975). RN [8] RP PROTEIN SEQUENCE OF 1-59; 96-101; 206-215 AND 328-347. RX PubMed=4571224; DOI=10.1016/s0021-9258(19)44452-9; RA Platt T., Files J.G., Weber K.; RT "Lac repressor. Specific proteolytic destruction of the NH 2 -terminal RT region and loss of the deoxyribonucleic acid-binding activity."; RL J. Biol. Chem. 248:110-121(1973). RN [9] RP PROTEIN SEQUENCE OF 60-70; 73-78 AND 83-86. RX PubMed=4594037; DOI=10.1073/pnas.70.11.3165; RA Ganem D., Miller J.H., Files J.G., Platt T., Weber K.; RT "Reinitiation of a lac repressor fragment at a condon other than AUG."; RL Proc. Natl. Acad. Sci. U.S.A. 70:3165-3169(1973). RN [10] RP NUCLEOTIDE SEQUENCE [GENOMIC DNA] OF 1-60. RX PubMed=3286877; DOI=10.1016/0022-2836(88)90237-9; RA Gordon A.J.E., Burns P.A., Fix D.F., Yatagai F., Allen F.L., Horsfall M.J., RA Halliday J.A., Gray J., Bernelot-Moens C., Glickman B.W.; RT "Missense mutation in the lacI gene of Escherichia coli. Inferences on the RT structure of the repressor protein."; RL J. Mol. Biol. 200:239-251(1988). RN [11] RP PROTEIN SEQUENCE OF 1-35. RX PubMed=7498473; DOI=10.1016/0014-5793(95)01153-6; RA Kamashev D.E., Esipova N.G., Ebralidse K.K., Mirzabekov A.D.; RT "Mechanism of Lac repressor switch-off: orientation of the Lac repressor RT DNA-binding domain is reversed upon inducer binding."; RL FEBS Lett. 375:27-30(1995). RN [12] RP MUTAGENESIS. RX PubMed=2178920; DOI=10.1002/j.1460-2075.1990.tb08153.x; RA Lehming N., Sartorius J., Kisters-Woike B., von Wilcken-Bergmann B., RA Mueller-Hill B.; RT "Mutant lac repressors with new specificities hint at rules for protein-DNA RT recognition."; RL EMBO J. 9:615-621(1990). RN [13] RP MUTAGENESIS. RX PubMed=8046748; DOI=10.1006/jmbi.1994.1458; RA Markiewicz P., Kleina L.G., Cruz C., Ehret S., Miller J.H.; RT "Genetic studies of the lac repressor. XIV. Analysis of 4000 altered RT Escherichia coli lac repressors reveals essential and non-essential RT residues, as well as 'spacers' which do not require a specific sequence."; RL J. Mol. Biol. 240:421-433(1994). RN [14] RP IDENTIFICATION BY 2D-GEL. RX PubMed=9298644; DOI=10.1002/elps.1150180805; RA VanBogelen R.A., Abshire K.Z., Moldover B., Olson E.R., Neidhardt F.C.; RT "Escherichia coli proteome analysis using the gene-protein database."; RL Electrophoresis 18:1243-1251(1997). RN [15] RP 3D-STRUCTURE MODELING. RX PubMed=2040302; DOI=10.1111/j.1432-1033.1991.tb16030.x; RA Kisters-Woike B., Lehming N., Sartorius J., von Wilcken-Bergmann B., RA Mueller-Hill B.; RT "A model of the lac repressor-operator complex based on physical and RT genetic data."; RL Eur. J. Biochem. 198:411-419(1991). RN [16] RP 3D-STRUCTURE MODELING OF 1-56. RX PubMed=1923807; DOI=10.1093/nar/19.19.5233; RA Shin J.A., Ebright R.H., Dervan P.B.; RT "Orientation of the Lac repressor DNA binding domain in complex with the RT left lac operator half site characterized by affinity cleaving."; RL Nucleic Acids Res. 19:5233-5236(1991). RN [17] RP STRUCTURE BY NMR. RX PubMed=3064080; RA Boelens R., Lamerichs R.M.J.N., Rullmann J.A.C., van Boom J.H., Kaptein R.; RT "The interaction of lac repressor headpiece with its operator: an NMR RT view."; RL Protein Seq. Data Anal. 1:487-498(1988). RN [18] RP STRUCTURE BY NMR. RX PubMed=2742823; DOI=10.1021/bi00433a037; RA Lamerichs R.M.J.N., Boelens R., van der Marel G.A., van Boom J.H., RA Kaptein R., Buck F., Fera B., Rueterjans H.; RT "H NMR study of a complex between the lac repressor headpiece and a 22 base RT pair symmetric lac operator."; RL Biochemistry 28:2985-2991(1989). RN [19] RP STRUCTURE BY NMR OF 1-56. RX PubMed=8683581; DOI=10.1006/jmbi.1996.0356; RA Slijper M., Bonvin A.M., Boelens R., Kaptein R.; RT "Refined structure of lac repressor headpiece (1-56) determined by RT relaxation matrix calculations from 2D and 3D NOE data: change of tertiary RT structure upon binding to the lac operator."; RL J. Mol. Biol. 259:761-773(1996). RN [20] RP STRUCTURE BY NMR OF 1-62. RX PubMed=10647179; DOI=10.1016/s0969-2126(00)88339-2; RA Spronk C.A., Bonvin A.M., Radha P.K., Melacini G., Boelens R., Kaptein R.; RT "The solution structure of Lac repressor headpiece 62 complexed to a RT symmetrical lac operator."; RL Structure 7:1483-1492(1999). RN [21] RP X-RAY CRYSTALLOGRAPHY (4.8 ANGSTROMS). RX PubMed=8638105; DOI=10.1126/science.271.5253.1247; RA Lewis M., Chang G., Horton N.C., Kercher M.A., Pace H.C., Schumacher M.A., RA Brennan R.G., Lu P.; RT "Crystal structure of the lactose operon repressor and its complexes with RT DNA and inducer."; RL Science 271:1247-1254(1996). CC -!- FUNCTION: Repressor of the lactose operon. Binds allolactose as an CC inducer. CC -!- SUBUNIT: Homotetramer. CC -!- INTERACTION: CC P03023; P03023: lacI; NbExp=3; IntAct=EBI-909231, EBI-909231; CC -!- MISCELLANEOUS: Removing residues 1-59 results in loss of DNA-binding CC activity but retains tetrameric structure and inducer-binding activity. CC Deleting residues 340-360 results in loss of tetramer formation, but CC retains dimer formation, inducer-binding activity, and DNA-binding CC activity (if residues 1-59 are present). CC -!- SEQUENCE CAUTION: CC Sequence=AAB18069.1; Type=Erroneous initiation; Evidence={ECO:0000305}; CC Sequence=AAB47270.1; Type=Erroneous initiation; Evidence={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; V00294; CAA23569.1; -; Genomic_DNA. DR EMBL; X58469; CAA41383.1; -; Genomic_DNA. DR EMBL; U86347; AAB47270.1; ALT_INIT; Genomic_DNA. DR EMBL; J01636; AAA24052.1; -; Genomic_DNA. DR EMBL; U72488; AAB36549.1; -; Genomic_DNA. DR EMBL; U78872; AAB37348.1; -; Genomic_DNA. DR EMBL; U78873; AAB37351.1; -; Genomic_DNA. DR EMBL; U78874; AAB37354.1; -; Genomic_DNA. DR EMBL; U73857; AAB18069.1; ALT_INIT; Genomic_DNA. DR EMBL; U00096; AAC73448.1; -; Genomic_DNA. DR EMBL; AP009048; BAE76127.1; -; Genomic_DNA. DR PIR; A93198; RPECL. DR RefSeq; NP_414879.3; NC_000913.3. DR RefSeq; WP_000805902.1; NZ_STEB01000036.1. DR PDB; 1CJG; NMR; -; A/B=1-62. DR PDB; 1EFA; X-ray; 2.60 A; A/B/C=1-333. DR PDB; 1JWL; X-ray; 4.00 A; A/B/C=1-333. DR PDB; 1JYE; X-ray; 1.70 A; A=1-349. DR PDB; 1JYF; X-ray; 3.00 A; A=1-349. DR PDB; 1L1M; NMR; -; A/B=1-62. DR PDB; 1LBG; X-ray; 4.80 A; A/B/C/D=1-360. DR PDB; 1LBH; X-ray; 3.20 A; A/B/C/D=1-360. DR PDB; 1LBI; X-ray; 2.70 A; A/B/C/D=1-360. DR PDB; 1LCC; NMR; -; A=1-51. DR PDB; 1LCD; NMR; -; A=1-51. DR PDB; 1LQC; NMR; -; A=1-56. DR PDB; 1OSL; NMR; -; A/B=1-62. DR PDB; 1TLF; X-ray; 2.60 A; A/B/C/D=60-360. DR PDB; 2BJC; NMR; -; A/B=1-62. DR PDB; 2KEI; NMR; -; A/B=1-62. DR PDB; 2KEJ; NMR; -; A/B=1-62. DR PDB; 2KEK; NMR; -; A/B=1-62. DR PDB; 2P9H; X-ray; 2.00 A; A/B=62-330. DR PDB; 2PAF; X-ray; 3.50 A; A/B=62-330. DR PDB; 2PE5; X-ray; 3.50 A; A/B/C=2-331. DR PDB; 3EDC; X-ray; 2.10 A; A/B/C/D=1-360. DR PDB; 4RZS; X-ray; 2.71 A; A/B/C/D=2-360. DR PDB; 4RZT; X-ray; 3.10 A; A/B/C/D=2-360. DR PDBsum; 1CJG; -. DR PDBsum; 1EFA; -. DR PDBsum; 1JWL; -. DR PDBsum; 1JYE; -. DR PDBsum; 1JYF; -. DR PDBsum; 1L1M; -. DR PDBsum; 1LBG; -. DR PDBsum; 1LBH; -. DR PDBsum; 1LBI; -. DR PDBsum; 1LCC; -. DR PDBsum; 1LCD; -. DR PDBsum; 1LQC; -. DR PDBsum; 1OSL; -. DR PDBsum; 1TLF; -. DR PDBsum; 2BJC; -. DR PDBsum; 2KEI; -. DR PDBsum; 2KEJ; -. DR PDBsum; 2KEK; -. DR PDBsum; 2P9H; -. DR PDBsum; 2PAF; -. DR PDBsum; 2PE5; -. DR PDBsum; 3EDC; -. DR PDBsum; 4RZS; -. DR PDBsum; 4RZT; -. DR AlphaFoldDB; P03023; -. DR BMRB; P03023; -. DR SMR; P03023; -. DR BioGRID; 4260668; 101. DR BioGRID; 849401; 1. DR DIP; DIP-10079N; -. DR IntAct; P03023; 6. DR MINT; P03023; -. DR STRING; 511145.b0345; -. DR DrugBank; DB01862; Isopropyl beta-D-thiogalactopyranoside. DR DrugBank; DB08297; ORTHONITROPHENYL-BETA-D-FUCOPYRANOSIDE. DR jPOST; P03023; -. DR PaxDb; 511145-b0345; -. DR EnsemblBacteria; AAC73448; AAC73448; b0345. DR GeneID; 78134078; -. DR GeneID; 945007; -. DR KEGG; ecj:JW0336; -. DR KEGG; eco:b0345; -. DR PATRIC; fig|511145.12.peg.353; -. DR EchoBASE; EB0520; -. DR eggNOG; COG1609; Bacteria. DR HOGENOM; CLU_037628_6_4_6; -. DR InParanoid; P03023; -. DR OMA; EPFEYSR; -. DR OrthoDB; 9798934at2; -. DR PhylomeDB; P03023; -. DR BioCyc; EcoCyc:PD00763; -. DR EvolutionaryTrace; P03023; -. DR PRO; PR:P03023; -. DR Proteomes; UP000000318; Chromosome. DR Proteomes; UP000000625; Chromosome. DR GO; GO:0005829; C:cytosol; HDA:UniProtKB. DR GO; GO:0000987; F:cis-regulatory region sequence-specific DNA binding; IDA:EcoCyc. DR GO; GO:0003700; F:DNA-binding transcription factor activity; IBA:GO_Central. DR GO; GO:0001217; F:DNA-binding transcription repressor activity; IDA:EcoCyc. DR GO; GO:0042802; F:identical protein binding; IPI:IntAct. DR GO; GO:0000976; F:transcription cis-regulatory region binding; IBA:GO_Central. DR GO; GO:0045892; P:negative regulation of DNA-templated transcription; IMP:EcoCyc. DR GO; GO:0006355; P:regulation of DNA-templated transcription; IBA:GO_Central. DR CDD; cd01392; HTH_LacI; 1. DR CDD; cd01537; PBP1_repressor_sugar_binding-like; 1. DR Gene3D; 3.40.50.2300; -; 2. DR Gene3D; 1.10.260.40; lambda repressor-like DNA-binding domains; 1. DR InterPro; IPR000843; HTH_LacI. DR InterPro; IPR046335; LacI/GalR-like_sensor. DR InterPro; IPR010982; Lambda_DNA-bd_dom_sf. DR InterPro; IPR028082; Peripla_BP_I. DR PANTHER; PTHR30146; LACI-RELATED TRANSCRIPTIONAL REPRESSOR; 1. DR PANTHER; PTHR30146:SF143; LACTOSE OPERON REPRESSOR; 1. DR Pfam; PF00356; LacI; 1. DR Pfam; PF13377; Peripla_BP_3; 1. DR PRINTS; PR00036; HTHLACI. DR SMART; SM00354; HTH_LACI; 1. DR SUPFAM; SSF47413; lambda repressor-like DNA-binding domains; 1. DR SUPFAM; SSF53822; Periplasmic binding protein-like I; 1. DR PROSITE; PS00356; HTH_LACI_1; 1. DR PROSITE; PS50932; HTH_LACI_2; 1. PE 1: Evidence at protein level; KW 3D-structure; Direct protein sequencing; DNA-binding; Reference proteome; KW Repressor; Transcription; Transcription regulation. FT CHAIN 1..360 FT /note="Lactose operon repressor" FT /id="PRO_0000107963" FT DOMAIN 1..58 FT /note="HTH lacI-type" FT /evidence="ECO:0000255|PROSITE-ProRule:PRU00111" FT DNA_BIND 6..25 FT /note="H-T-H motif" FT /evidence="ECO:0000255|PROSITE-ProRule:PRU00111" FT VARIANT 282 FT /note="Y -> D (in T41 mutant)" FT MUTAGEN 17 FT /note="Y->H: Broadening of specificity." FT MUTAGEN 22 FT /note="R->N: Recognizes an operator variant." FT CONFLICT 286 FT /note="L -> S (in Ref. 1, 4 and 7)" FT /evidence="ECO:0000305" FT HELIX 6..11 FT /evidence="ECO:0007829|PDB:1EFA" FT TURN 12..14 FT /evidence="ECO:0007829|PDB:1EFA" FT HELIX 17..24 FT /evidence="ECO:0007829|PDB:1EFA" FT TURN 25..27 FT /evidence="ECO:0007829|PDB:1LQC" FT STRAND 28..30 FT /evidence="ECO:0007829|PDB:1CJG" FT HELIX 33..45 FT /evidence="ECO:0007829|PDB:1EFA" FT HELIX 51..56 FT /evidence="ECO:0007829|PDB:1EFA" FT HELIX 58..61 FT /evidence="ECO:0007829|PDB:2BJC" FT STRAND 63..69 FT /evidence="ECO:0007829|PDB:1JYE" FT HELIX 74..89 FT /evidence="ECO:0007829|PDB:1JYE" FT STRAND 93..98 FT /evidence="ECO:0007829|PDB:1JYE" FT STRAND 101..103 FT /evidence="ECO:0007829|PDB:1JYE" FT HELIX 104..115 FT /evidence="ECO:0007829|PDB:1JYE" FT TURN 116..118 FT /evidence="ECO:0007829|PDB:1JYE" FT STRAND 122..126 FT /evidence="ECO:0007829|PDB:1JYE" FT HELIX 130..139 FT /evidence="ECO:0007829|PDB:1JYE" FT TURN 140..142 FT /evidence="ECO:0007829|PDB:1JYE" FT STRAND 145..150 FT /evidence="ECO:0007829|PDB:1JYE" FT STRAND 154..156 FT /evidence="ECO:0007829|PDB:1JYE" FT STRAND 158..161 FT /evidence="ECO:0007829|PDB:1JYE" FT HELIX 163..177 FT /evidence="ECO:0007829|PDB:1JYE" FT STRAND 181..186 FT /evidence="ECO:0007829|PDB:1JYE" FT HELIX 192..207 FT /evidence="ECO:0007829|PDB:1JYE" FT STRAND 213..217 FT /evidence="ECO:0007829|PDB:1JYE" FT HELIX 222..234 FT /evidence="ECO:0007829|PDB:1JYE" FT STRAND 240..246 FT /evidence="ECO:0007829|PDB:1JYE" FT HELIX 247..259 FT /evidence="ECO:0007829|PDB:1JYE" FT TURN 265..267 FT /evidence="ECO:0007829|PDB:1JYE" FT STRAND 268..271 FT /evidence="ECO:0007829|PDB:1JYE" FT HELIX 277..281 FT /evidence="ECO:0007829|PDB:1JYE" FT STRAND 282..284 FT /evidence="ECO:0007829|PDB:1JYE" FT STRAND 287..290 FT /evidence="ECO:0007829|PDB:1JYE" FT HELIX 293..308 FT /evidence="ECO:0007829|PDB:1JYE" FT STRAND 314..319 FT /evidence="ECO:0007829|PDB:1JYE" FT STRAND 322..324 FT /evidence="ECO:0007829|PDB:1JYE" FT STRAND 333..338 FT /evidence="ECO:0007829|PDB:1LBH" FT HELIX 339..354 FT /evidence="ECO:0007829|PDB:3EDC" SQ SEQUENCE 360 AA; 38590 MW; 347A8DEE92D736CB CRC64; MKPVTLYDVA EYAGVSYQTV SRVVNQASHV SAKTREKVEA AMAELNYIPN RVAQQLAGKQ SLLIGVATSS LALHAPSQIV AAIKSRADQL GASVVVSMVE RSGVEACKAA VHNLLAQRVS GLIINYPLDD QDAIAVEAAC TNVPALFLDV SDQTPINSII FSHEDGTRLG VEHLVALGHQ QIALLAGPLS SVSARLRLAG WHKYLTRNQI QPIAEREGDW SAMSGFQQTM QMLNEGIVPT AMLVANDQMA LGAMRAITES GLRVGADISV VGYDDTEDSS CYIPPLTTIK QDFRLLGQTS VDRLLQLSQG QAVKGNQLLP VSLVKRKTTL APNTQTASPR ALADSLMQLA RQVSRLESGQ //