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Protein

Lactose permease

Gene

lacY

Organism
Escherichia coli (strain K12)
Status
Reviewed-Annotation score: -Experimental evidence at protein leveli

Functioni

Responsible for transport of beta-galactosides into the cell, with the concomitant import of a proton (symport system). Can transport lactose, melibiose, lactulose or the analog methyl-1-thio-beta,D-galactopyranoside (TMG), but not sucrose or fructose (PubMed:1848449, PubMed:18177889, PubMed:22106930). The substrate specificity is directed toward the galactopyranosyl moiety of the substrate (PubMed:22106930).3 Publications

Kineticsi

  1. KM=0.62 mM for lactose1 Publication
  2. KM=0.24 mM for melibiose1 Publication
  3. KM=0.24 mM for lactulose1 Publication
  4. KM=0.54 mM for TMG1 Publication
  1. Vmax=191 nmol/min/mg enzyme with lactose as substrate1 Publication
  2. Vmax=105 nmol/min/mg enzyme with melibiose as substrate1 Publication
  3. Vmax=49 nmol/min/mg enzyme with lactulose as substrate1 Publication
  4. Vmax=180 nmol/min/mg enzyme with TMG as substrate1 Publication

Sites

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Sitei126Substrate binding1 Publication1
Sitei144Substrate binding1 Publication1
Sitei269Substrate binding and proton translocation1 Publication1
Sitei302Proton translocation1 Publication1
Sitei322Proton translocation1 Publication1
Sitei325Proton translocation1 Publication1

GO - Molecular functioni

  • carbohydrate:proton symporter activity Source: EcoliWiki
  • lactose:proton symporter activity Source: EcoCyc
  • lactose binding Source: EcoliWiki

GO - Biological processi

  • carbohydrate transport Source: CACAO
  • lactose transport Source: EcoCyc

Keywordsi

Biological processSugar transport, Symport, Transport

Enzyme and pathway databases

BioCyciEcoCyc:LACY-MONOMER
MetaCyc:LACY-MONOMER

Protein family/group databases

TCDBi2.A.1.5.1 the major facilitator superfamily (mfs)

Names & Taxonomyi

Protein namesi
Recommended name:
Lactose permease1 Publication
Alternative name(s):
Lactose-proton symport
Gene namesi
Name:lacY1 Publication
Ordered Locus Names:b0343, JW0334
OrganismiEscherichia coli (strain K12)
Taxonomic identifieri83333 [NCBI]
Taxonomic lineageiBacteriaProteobacteriaGammaproteobacteriaEnterobacteralesEnterobacteriaceaeEscherichia
Proteomesi
  • UP000000318 Componenti: Chromosome
  • UP000000625 Componenti: Chromosome

Organism-specific databases

EcoGeneiEG10526 lacY

Subcellular locationi

Topology

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Topological domaini1 – 7Cytoplasmic1 Publication7
Transmembranei8 – 34Helical; Name=1Add BLAST27
Topological domaini35 – 41Periplasmic1 Publication7
Transmembranei42 – 70Helical; Name=2Add BLAST29
Topological domaini71 – 74Cytoplasmic1 Publication4
Transmembranei75 – 100Helical; Name=3Add BLAST26
Topological domaini101 – 104Periplasmic1 Publication4
Transmembranei105 – 129Helical; Name=4Add BLAST25
Topological domaini130 – 140Cytoplasmic1 PublicationAdd BLAST11
Transmembranei141 – 163Helical; Name=5Add BLAST23
Topological domaini164 – 166Periplasmic1 Publication3
Transmembranei167 – 186Helical; Name=6Add BLAST20
Topological domaini187 – 220Cytoplasmic1 PublicationAdd BLAST34
Transmembranei221 – 249Helical; Name=7Add BLAST29
Topological domaini250 – 253Periplasmic1 Publication4
Transmembranei254 – 278Helical; Name=8Add BLAST25
Topological domaini279 – 288Cytoplasmic1 Publication10
Transmembranei289 – 308Helical; Name=9Add BLAST20
Topological domaini309 – 311Periplasmic1 Publication3
Transmembranei312 – 334Helical; Name=10Add BLAST23
Topological domaini335 – 346Cytoplasmic1 PublicationAdd BLAST12
Transmembranei347 – 374Helical; Name=11Add BLAST28
Topological domaini375 – 377Periplasmic1 Publication3
Transmembranei378 – 398Helical; Name=12Add BLAST21
Topological domaini399 – 417Cytoplasmic2 PublicationsAdd BLAST19

GO - Cellular componenti

  • integral component of membrane Source: EcoliWiki
  • integral component of plasma membrane Source: EcoCyc
  • membrane Source: EcoliWiki
  • plasma membrane Source: EcoCyc

Keywords - Cellular componenti

Cell inner membrane, Cell membrane, Membrane

Pathology & Biotechi

Mutagenesis

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Mutagenesisi65L → V: No change in transport activity. 1 Publication1
Mutagenesisi96G → A: No change in transport activity. 1 Publication1
Mutagenesisi122A → S: No change in transport activity. 1 Publication1
Mutagenesisi237D → N or G: Loss of activity. 1 Publication1
Mutagenesisi264V → A: No change in transport activity. 1 Publication1
Mutagenesisi279A → S: No change in transport activity. 1 Publication1
Mutagenesisi355C → Q: No change in transport activity. 1 Publication1
Mutagenesisi358K → T: Loss of activity. 1 Publication1
Mutagenesisi367V → A: Increases transport of melibiose and impairs transport of TMG. 1 Publication1

Chemistry databases

DrugBankiDB04396 Thiodigalactoside

PTM / Processingi

Molecule processing

Feature keyPosition(s)DescriptionActionsGraphical viewLength
ChainiPRO_00001961841 – 417Lactose permeaseAdd BLAST417

Amino acid modifications

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Modified residuei1N-formylmethionine; partial1 Publication1

Keywords - PTMi

Formylation

Proteomic databases

PaxDbiP02920
PRIDEiP02920

Interactioni

Subunit structurei

Monomer.

Protein-protein interaction databases

BioGridi4263185, 8 interactors
DIPiDIP-10080N
STRINGi316385.ECDH10B_1356

Structurei

Secondary structure

1417
Legend: HelixTurnBeta strandPDB Structure known for this area
Show more details
Feature keyPosition(s)DescriptionActionsGraphical viewLength
Turni2 – 4Combined sources3
Helixi7 – 26Combined sources20
Turni27 – 29Combined sources3
Helixi30 – 35Combined sources6
Turni36 – 38Combined sources3
Turni42 – 44Combined sources3
Helixi46 – 67Combined sources22
Helixi68 – 70Combined sources3
Helixi71 – 73Combined sources3
Helixi75 – 82Combined sources8
Helixi84 – 86Combined sources3
Helixi87 – 93Combined sources7
Helixi95 – 100Combined sources6
Helixi105 – 108Combined sources4
Helixi109 – 111Combined sources3
Helixi116 – 119Combined sources4
Helixi122 – 136Combined sources15
Helixi140 – 143Combined sources4
Beta strandi144 – 146Combined sources3
Turni147 – 149Combined sources3
Helixi150 – 164Combined sources15
Helixi167 – 170Combined sources4
Turni171 – 179Combined sources9
Helixi180 – 183Combined sources4
Beta strandi193 – 195Combined sources3
Beta strandi197 – 203Combined sources7
Helixi210 – 216Combined sources7
Helixi220 – 249Combined sources30
Beta strandi251 – 253Combined sources3
Helixi254 – 257Combined sources4
Helixi259 – 286Combined sources28
Helixi288 – 306Combined sources19
Helixi312 – 318Combined sources7
Helixi321 – 340Combined sources20
Helixi343 – 354Combined sources12
Turni355 – 357Combined sources3
Helixi358 – 365Combined sources8
Helixi367 – 370Combined sources4
Helixi372 – 375Combined sources4
Helixi377 – 396Combined sources20
Beta strandi408 – 413Combined sources6
Turni414 – 416Combined sources3

3D structure databases

Select the link destinations:
PDBei
RCSB PDBi
PDBji
Links Updated
PDB entryMethodResolution (Å)ChainPositionsPDBsum
1M2Umodel-A1-417[»]
1PV6X-ray3.50A/B1-417[»]
1PV7X-ray3.60A/B1-417[»]
2CFPX-ray3.30A1-417[»]
2CFQX-ray2.95A1-417[»]
2V8NX-ray3.60A/B1-417[»]
2Y5YX-ray3.38A/B1-417[»]
4ZYRX-ray3.31A/B1-417[»]
5GXBX-ray3.30A1-417[»]
ProteinModelPortaliP02920
SMRiP02920
ModBaseiSearch...
MobiDBiSearch...

Miscellaneous databases

EvolutionaryTraceiP02920

Family & Domainsi

Sequence similaritiesi

Keywords - Domaini

Transmembrane, Transmembrane helix

Phylogenomic databases

eggNOGiENOG4105U0F Bacteria
ENOG410XQTD LUCA
HOGENOMiHOG000114363
InParanoidiP02920
KOiK02532
OMAiIVGCFKY
PhylomeDBiP02920

Family and domain databases

CDDicd06174 MFS, 1 hit
InterProiView protein in InterPro
IPR000576 LacY/RafB_perm_fam
IPR018457 LacY/RafB_perm_fam_CS
IPR020846 MFS_dom
IPR036259 MFS_trans_sf
PfamiView protein in Pfam
PF01306 LacY_symp, 1 hit
PRINTSiPR00174 LACYSMPORT
SUPFAMiSSF103473 SSF103473, 1 hit
TIGRFAMsiTIGR00882 2A0105, 1 hit
PROSITEiView protein in PROSITE
PS00896 LACY_1, 1 hit
PS00897 LACY_2, 1 hit
PS50850 MFS, 1 hit

Sequencei

Sequence statusi: Complete.

P02920-1 [UniParc]FASTAAdd to basket

« Hide

        10         20         30         40         50
MYYLKNTNFW MFGLFFFFYF FIMGAYFPFF PIWLHDINHI SKSDTGIIFA
60 70 80 90 100
AISLFSLLFQ PLFGLLSDKL GLRKYLLWII TGMLVMFAPF FIFIFGPLLQ
110 120 130 140 150
YNILVGSIVG GIYLGFCFNA GAPAVEAFIE KVSRRSNFEF GRARMFGCVG
160 170 180 190 200
WALCASIVGI MFTINNQFVF WLGSGCALIL AVLLFFAKTD APSSATVANA
210 220 230 240 250
VGANHSAFSL KLALELFRQP KLWFLSLYVI GVSCTYDVFD QQFANFFTSF
260 270 280 290 300
FATGEQGTRV FGYVTTMGEL LNASIMFFAP LIINRIGGKN ALLLAGTIMS
310 320 330 340 350
VRIIGSSFAT SALEVVILKT LHMFEVPFLL VGCFKYITSQ FEVRFSATIY
360 370 380 390 400
LVCFCFFKQL AMIFMSVLAG NMYESIGFQG AYLVLGLVAL GFTLISVFTL
410
SGPGPLSLLR RQVNEVA
Length:417
Mass (Da):46,503
Last modified:July 21, 1986 - v1
Checksum:i24A8062F628CDA32
GO

Mass spectrometryi

Molecular mass is 47357 Da from positions 1 - 417. Determined by ESI. 1 Publication

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
J01636 Genomic DNA Translation: AAA24054.1
V00295 Genomic DNA Translation: CAA23571.1
X56095 Genomic DNA Translation: CAA39575.1
U73857 Genomic DNA Translation: AAB18067.1
U00096 Genomic DNA Translation: AAC73446.1
AP009048 Genomic DNA Translation: BAE76125.1
PIRiA03418 GREC
RefSeqiNP_414877.1, NC_000913.3
WP_000291549.1, NZ_LN832404.1

Genome annotation databases

EnsemblBacteriaiAAC73446; AAC73446; b0343
BAE76125; BAE76125; BAE76125
GeneIDi949083
KEGGiecj:JW0334
eco:b0343
PATRICifig|1411691.4.peg.1934

Similar proteinsi

Entry informationi

Entry nameiLACY_ECOLI
AccessioniPrimary (citable) accession number: P02920
Secondary accession number(s): Q2MC81
Entry historyiIntegrated into UniProtKB/Swiss-Prot: July 21, 1986
Last sequence update: July 21, 1986
Last modified: April 25, 2018
This is version 165 of the entry and version 1 of the sequence. See complete history.
Entry statusiReviewed (UniProtKB/Swiss-Prot)
Annotation programProkaryotic Protein Annotation Program

Miscellaneousi

Keywords - Technical termi

3D-structure, Complete proteome, Reference proteome

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