P03023 (LACI_ECOLI) Reviewed, UniProtKB/Swiss-Prot

Names and origin

Protein names

Recommended name:
Lactose operon repressor

Gene names

Name:	lacI
Ordered Locus Names:	b0345, JW0336

Organism

Escherichia coli (strain K12)

Taxonomic identifier

83333 [NCBI]

Taxonomic lineage

Bacteria › Proteobacteria › Gammaproteobacteria › Enterobacteriales › Enterobacteriaceae › Escherichia

Protein attributes

Sequence length	360 AA.
Sequence status	Complete.
Protein existence	Evidence at protein level

General annotation (Comments)

Function	Repressor of the lactose operon. Binds allolactose as an inducer.
Subunit structure	Homotetramer.
Miscellaneous	Removing residues 1-59 results in loss of DNA-binding activity but retains tetrameric structure and inducer-binding activity. Deleting residues 340-360 results in loss of tetramer formation, but retains dimer formation, inducer-binding activity, and DNA-binding activity (if residues 1-59 are present).
Sequence similarities	Contains 1 HTH lacI-type DNA-binding domain.
Sequence caution	The sequence AAB18069.1 differs from that shown. Reason: Erroneous initiation. The sequence AAB47270.1 differs from that shown. Reason: Erroneous initiation.

Ontologies

Keywords
Biological process	Transcription Transcription regulation
Ligand	DNA-binding
Molecular function	Repressor
Technical term	3D-structure Complete proteome Direct protein sequencing Reference proteome
Gene Ontology (GO)
Biological process	transcription, DNA-dependent Inferred from electronic annotation. Source: UniProtKB-KW
Cellular component	cytosol Inferred from direct assay. Source: UniProtKB
Molecular function	DNA binding Inferred from electronic annotation. Source: UniProtKB-KW sequence-specific DNA binding transcription factor activity Inferred from electronic annotation. Source: InterPro
Complete GO annotation...

Sequence annotation (Features)

Feature key

Position(s)

Length

Description

Graphical view

Feature identifier

Molecule processing

Chain

1 – 360

360

Lactose operon repressor

PRO_0000107963

Regions

Domain

1 – 58

58

HTH lacI-type

DNA binding

6 – 25

20

H-T-H motif

Natural variations

Natural variant

282

1

Y → D in T41 mutant.

Experimental info

Mutagenesis

17

1

Y → H: Broadening of specificity.

Mutagenesis

22

1

R → N: Recognizes an operator variant.

Sequence conflict

286

1

L → S Ref.1

Sequence conflict

286

1

L → S Ref.4

Sequence conflict

286

1

L → S Ref.7

Secondary structure

1

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360

Helix Strand Turn

Details...

Helix

6 – 11

6

Turn

12 – 14

3

Helix

17 – 24

8

Helix

33 – 45

13

Helix

51 – 56

6

Beta strand

63 – 69

7

Helix

74 – 89

16

Beta strand

93 – 98

6

Beta strand

101 – 103

3

Helix

104 – 115

12

Turn

116 – 118

3

Beta strand

122 – 126

5

Helix

130 – 139

10

Turn

140 – 142

3

Beta strand

145 – 150

6

Beta strand

154 – 156

3

Beta strand

158 – 161

4

Helix

163 – 177

15

Beta strand

181 – 186

6

Helix

192 – 207

16

Beta strand

213 – 217

5

Helix

222 – 234

13

Beta strand

240 – 246

7

Helix

247 – 259

13

Turn

265 – 267

3

Beta strand

268 – 271

4

Helix

277 – 281

5

Beta strand

282 – 284

3

Beta strand

287 – 290

4

Helix

293 – 308

16

Beta strand

314 – 319

6

Beta strand

322 – 324

3

Beta strand

334 – 338

5

Helix

343 – 353

11

Helix

354 – 356

3

Sequences

	Sequence		Length	Mass (Da)
	P03023 [UniParc]. Last modified July 19, 2003. Version 3. Checksum: 347A8DEE92D736CB	FASTA	360	38,590
	10 20 30 40 50 60 MKPVTLYDVA EYAGVSYQTV SRVVNQASHV SAKTREKVEA AMAELNYIPN RVAQQLAGKQ 70 80 90 100 110 120 SLLIGVATSS LALHAPSQIV AAIKSRADQL GASVVVSMVE RSGVEACKAA VHNLLAQRVS 130 140 150 160 170 180 GLIINYPLDD QDAIAVEAAC TNVPALFLDV SDQTPINSII FSHEDGTRLG VEHLVALGHQ 190 200 210 220 230 240 QIALLAGPLS SVSARLRLAG WHKYLTRNQI QPIAEREGDW SAMSGFQQTM QMLNEGIVPT 250 260 270 280 290 300 AMLVANDQMA LGAMRAITES GLRVGADISV VGYDDTEDSS CYIPPLTTIK QDFRLLGQTS 310 320 330 340 350 360 VDRLLQLSQG QAVKGNQLLP VSLVKRKTTL APNTQTASPR ALADSLMQLA RQVSRLESGQ

References

	« Hide 'large scale' referencesShow 'large scale' references »
[1]	"Sequence of the lacI gene." Farabaugh P.J. Nature 274:765-769(1978) [PubMed: 355891] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA].
[2]	Chen J., Matthews K.K.S.M. Submitted (MAY-1991) to the EMBL/GenBank/DDBJ databases Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA].
[3]	Marsh S. Submitted (JAN-1997) to the EMBL/GenBank/DDBJ databases Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA].
[4]	"Sequence of minutes 4-25 of Escherichia coli." Chung E., Allen E., Araujo R., Aparicio A.M., Davis K., Duncan M., Federspiel N., Hyman R., Kalman S., Komp C., Kurdi O., Lew H., Lin D., Namath A., Oefner P., Roberts D., Schramm S., Davis R.W. Submitted (JAN-1997) to the EMBL/GenBank/DDBJ databases Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA]. Strain: K12 / MG1655 / ATCC 47076.
[5]	"The complete genome sequence of Escherichia coli K-12." Blattner F.R., Plunkett G. III, Bloch C.A., Perna N.T., Burland V., Riley M., Collado-Vides J., Glasner J.D., Rode C.K., Mayhew G.F., Gregor J., Davis N.W., Kirkpatrick H.A., Goeden M.A., Rose D.J., Mau B., Shao Y. Science 277:1453-1474(1997) [PubMed: 9278503] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA]. Strain: K12 / MG1655 / ATCC 47076.
[6]	"Highly accurate genome sequences of Escherichia coli K-12 strains MG1655 and W3110." Hayashi K., Morooka N., Yamamoto Y., Fujita K., Isono K., Choi S., Ohtsubo E., Baba T., Wanner B.L., Mori H., Horiuchi T. Mol. Syst. Biol. 2:E1-E5(2006) [PubMed: 16738553] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA]. Strain: K12 / W3110 / ATCC 27325 / DSM 5911.
[7]	"Amino-acid sequence of lac repressor from Escherichia coli. Isolation, sequence analysis and sequence assembly of tryptic peptides and cyanogen-bromide fragments." Beyreuther K., Adler K., Fanning E., Murray C., Klemm A., Geisler N. Eur. J. Biochem. 59:491-509(1975) [PubMed: 1107032] [Abstract] Cited for: PROTEIN SEQUENCE OF 1-147; 159-230 AND 233-360.
[8]	"Lac repressor. Specific proteolytic destruction of the NH 2 -terminal region and loss of the deoxyribonucleic acid-binding activity." Platt T., Files J.G., Weber K. J. Biol. Chem. 248:110-121(1973) [PubMed: 4571224] [Abstract] Cited for: PROTEIN SEQUENCE OF 1-59; 96-101; 206-215 AND 328-347.
[9]	"Reinitiation of a lac repressor fragment at a condon other than AUG." Ganem D., Miller J.H., Files J.G., Platt T., Weber K. Proc. Natl. Acad. Sci. U.S.A. 70:3165-3169(1973) [PubMed: 4594037] [Abstract] Cited for: PROTEIN SEQUENCE OF 60-70; 73-78 AND 83-86.
[10]	"Missense mutation in the lacI gene of Escherichia coli. Inferences on the structure of the repressor protein." Gordon A.J.E., Burns P.A., Fix D.F., Yatagai F., Allen F.L., Horsfall M.J., Halliday J.A., Gray J., Bernelot-Moens C., Glickman B.W. J. Mol. Biol. 200:239-251(1988) [PubMed: 3286877] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA] OF 1-60.
[11]	"Mechanism of Lac repressor switch-off: orientation of the Lac repressor DNA-binding domain is reversed upon inducer binding." Kamashev D.E., Esipova N.G., Ebralidse K.K., Mirzabekov A.D. FEBS Lett. 375:27-30(1995) [PubMed: 7498473] [Abstract] Cited for: PROTEIN SEQUENCE OF 1-35.
[12]	"Mutant lac repressors with new specificities hint at rules for protein-DNA recognition." Lehming N., Sartorius J., Kisters-Woike B., von Wilcken-Bergmann B., Mueller-Hill B. EMBO J. 9:615-621(1990) [PubMed: 2178920] [Abstract] Cited for: MUTAGENESIS.
[13]	"Genetic studies of the lac repressor. XIV. Analysis of 4000 altered Escherichia coli lac repressors reveals essential and non-essential residues, as well as 'spacers' which do not require a specific sequence." Markiewicz P., Kleina L.G., Cruz C., Ehret S., Miller J.H. J. Mol. Biol. 240:421-433(1994) [PubMed: 8046748] [Abstract] Cited for: MUTAGENESIS.
[14]	"A model of the lac repressor-operator complex based on physical and genetic data." Kisters-Woike B., Lehming N., Sartorius J., von Wilcken-Bergmann B., Mueller-Hill B. Eur. J. Biochem. 198:411-419(1991) [PubMed: 2040302] [Abstract] Cited for: 3D-STRUCTURE MODELING.
[15]	"Orientation of the Lac repressor DNA binding domain in complex with the left lac operator half site characterized by affinity cleaving." Shin J.A., Ebright R.H., Dervan P.B. Nucleic Acids Res. 19:5233-5236(1991) [PubMed: 1923807] [Abstract] Cited for: 3D-STRUCTURE MODELING OF 1-56.
[16]	"The interaction of lac repressor headpiece with its operator: an NMR view." Boelens R., Lamerichs R.M.J.N., Rullmann J.A.C., van Boom J.H., Kaptein R. Protein Seq. Data Anal. 1:487-498(1988) [PubMed: 3064080] [Abstract] Cited for: STRUCTURE BY NMR.
[17]	"H NMR study of a complex between the lac repressor headpiece and a 22 base pair symmetric lac operator." Lamerichs R.M.J.N., Boelens R., van der Marel G.A., van Boom J.H., Kaptein R., Buck F., Fera B., Rueterjans H. Biochemistry 28:2985-2991(1989) [PubMed: 2742823] [Abstract] Cited for: STRUCTURE BY NMR.
[18]	"Refined structure of lac repressor headpiece (1-56) determined by relaxation matrix calculations from 2D and 3D NOE data: change of tertiary structure upon binding to the lac operator." Slijper M., Bonvin A.M., Boelens R., Kaptein R. J. Mol. Biol. 259:761-773(1996) [PubMed: 8683581] [Abstract] Cited for: STRUCTURE BY NMR OF 1-56.
[19]	"The solution structure of Lac repressor headpiece 62 complexed to a symmetrical lac operator." Spronk C.A., Bonvin A.M., Radha P.K., Melacini G., Boelens R., Kaptein R. Structure 7:1483-1492(1999) [PubMed: 10647179] [Abstract] Cited for: STRUCTURE BY NMR OF 1-62.
[20]	"Crystal structure of the lactose operon repressor and its complexes with DNA and inducer." Lewis M., Chang G., Horton N.C., Kercher M.A., Pace H.C., Schumacher M.A., Brennan R.G., Lu P. Science 271:1247-1254(1996) [PubMed: 8638105] [Abstract] Cited for: X-RAY CRYSTALLOGRAPHY (4.8 ANGSTROMS).
+	Additional computationally mapped references.

Cross-references

Sequence databases

EMBL
GenBank
DDBJ

V00294 Genomic DNA. Translation: CAA23569.1.
X58469 Genomic DNA. Translation: CAA41383.1.
U86347 Genomic DNA. Translation: AAB47270.1. Different initiation.
J01636 Genomic DNA. Translation: AAA24052.1.
U72488 Genomic DNA. Translation: AAB36549.1.
U78872 Genomic DNA. Translation: AAB37348.1.
U78873 Genomic DNA. Translation: AAB37351.1.
U78874 Genomic DNA. Translation: AAB37354.1.
U73857 Genomic DNA. Translation: AAB18069.1. Different initiation.
U00096 Genomic DNA. Translation: AAC73448.1.
AP009048 Genomic DNA. Translation: BAE76127.1.

PIR

RPECL. A93198.

RefSeq

NP_414879.3. NC_000913.2.

3D structure databases

PDBe
RCSB PDB
PDBj

Entry	Method	Resolution (Å)	Chain	Positions	PDBsum
1CJG	NMR	-	A/B	1-62	[»]
1EFA	X-ray	2.60	A/B/C	1-333	[»]
1JWL	X-ray	4.00	A/B/C	1-333	[»]
1JYE	X-ray	1.70	A	1-349	[»]
1JYF	X-ray	3.00	A	1-349	[»]
1L1M	NMR	-	A/B	1-62	[»]
1LBG	X-ray	4.80	A/B/C/D	1-360	[»]
1LBH	X-ray	3.20	A/B/C/D	1-360	[»]
1LBI	X-ray	2.70	A/B/C/D	1-360	[»]
1LCC	NMR	-	A	1-51	[»]
1LCD	NMR	-	A	1-51	[»]
1LQC	NMR	-	A	1-56	[»]
1LTP	model	-	L	62-323	[»]
1OSL	NMR	-	A/B	1-62	[»]
1TLF	X-ray	2.60	A/B/C/D	60-360	[»]
1Z04	model	-	A/B/C/D	1-357	[»]
2BJC	NMR	-	A/B	1-62	[»]
2KEI	NMR	-	A/B	1-62	[»]
2KEJ	NMR	-	A/B	1-62	[»]
2KEK	NMR	-	A/B	1-62	[»]
2P9H	X-ray	2.00	A/B	62-330	[»]
2PAF	X-ray	3.50	A/B	62-330	[»]
2PE5	X-ray	3.50	A/B/C	2-331	[»]
3EDC	X-ray	2.10	A/B/C/D	1-360	[»]

ProteinModelPortal

P03023.

SMR

P03023. Positions 1-360.

DisProt

DP00433.

ModBase

Search...

Protein-protein interaction databases

DIP

DIP-10079N.

IntAct

P03023. 7 interactions.

2D gel databases

ECO2DBASE

H039.0. 6TH EDITION.

Protocols and materials databases

StructuralBiologyKnowledgebase

Search...

Genome annotation databases

EnsemblBacteria

EBESCT00000002264; EBESCP00000002264; EBESCG00000001853.
EBESCT00000002265; EBESCP00000002265; EBESCG00000001853.
EBESCT00000014841; EBESCP00000014132; EBESCG00000013901.

GeneID

945007.

GenomeReviews

Gene locus JW0336 in contig AP009048_GR.
Gene locus b0345 in contig U00096_GR.

KEGG

ecj:JW0336.
eco:b0345.

PATRIC

32115823. VBIEscCol129921_0353.

Organism-specific databases

EchoBASE

EB0520.

EcoGene

EG10525. lacI.

Phylogenomic databases

eggNOG

COG1609.

GeneTree

EBGT00050000009236.

HOGENOM

HBG753640.

OMA

DIVPTAM.

PhylomeDB

P03023.

ProtClustDB

PRK09526.

Enzyme and pathway databases

BioCyc

EcoCyc:PD00763.

Gene expression databases

Genevestigator

P03023.

Family and domain databases

InterPro

IPR010982. Lambda_DNA-bd.
IPR001761. Peripla_BP_Lac1.
IPR000843. Tscrpt_reg_HTH_LacI.
[Graphical view]

Gene3D

G3DSA:1.10.260.40. G3DSA:1.10.260.40. 1 hit.

Pfam

PF00356. LacI. 1 hit.
PF00532. Peripla_BP_1. 1 hit.
[Graphical view]

PRINTS

PR00036. HTHLACI.

SMART

SM00354. HTH_LACI. 1 hit.
[Graphical view]

SUPFAM

SSF47413. Lambda_like_DNA. 1 hit.

PROSITE

PS00356. HTH_LACI_1. 1 hit.
PS50932. HTH_LACI_2. 1 hit.
[Graphical view]

ProtoNet

Search...

Entry information

Entry name

LACI_ECOLI

Accession

Primary (citable) accession number: P03023
Secondary accession number(s): O09196 , P71309, Q2MC79, Q47338

Entry history

Integrated into UniProtKB/Swiss-Prot:	July 21, 1986
Last sequence update:	July 19, 2003
Last modified:	January 25, 2012
This is version 131 of the entry and version 3 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation program

Prokaryotic Protein Annotation Program