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    lacY lactose permease [ Escherichia coli str. K-12 substr. MG1655 ]

    Gene ID: 949083, updated on 11-Apr-2024

    Summary

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    Gene symbol
    lacY
    Gene description
    lactose permease
    Primary source
    ASAP:ABE-0001181
    Locus tag
    b0343
    See related
    ECOCYC:EG10526
    Gene type
    protein coding
    RefSeq status
    PROVISIONAL
    Organism
    Escherichia coli str. K-12 substr. MG1655 (strain: K-12, substrain: MG1655)
    Lineage
    Bacteria; Pseudomonadota; Gammaproteobacteria; Enterobacterales; Enterobacteriaceae; Escherichia
    Also known as
    ECK0340
    Summary
    Major Facilitator Superfamily (MFS). [More information is available at EcoGene: EG10526]. The lactose permease LacY is a lactose/proton symporter, responsible for the uptake of lactose and other galactosides. [More information is available at EcoCyc: EG10526].
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    Genomic context

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    Sequence:
    NC_000913.3 (361926..363179, complement)

    NC_000913.3Genomic Context describing neighboring genes Neighboring gene cyanate transporter Neighboring gene galactoside O-acetyltransferase Neighboring gene beta-galactosidase Neighboring gene DNA-binding transcriptional repressor LacI

    Genomic regions, transcripts, and products

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    Genomic Sequence:
    NC_000913.3

    Go to nucleotide: Graphics FASTA GenBank

    Bibliography

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    Related articles in PubMed

    1. Diversity in kinetics correlated with structure in nano body-stabilized LacY. Kumar H, et al. PLoS One, 2020. PMID 32380514, Free PMC Article
    2. Structural and Functional Adaptability of Sucrose and Lactose Permeases from Escherichia coli to the Membrane Lipid Composition. Vitrac H, et al. Biochemistry, 2020 May 19. PMID 32363862, Free PMC Article
    3. Oversized galactosides as a probe for conformational dynamics in LacY. Smirnova I, et al. Proc Natl Acad Sci U S A, 2018 Apr 17. PMID 29602806, Free PMC Article
    4. pK(a) of Glu325 in LacY. Grytsyk N, et al. Proc Natl Acad Sci U S A, 2017 Feb 14. PMID 28154138, Free PMC Article
    5. Crystal structure of a LacY-nanobody complex in a periplasmic-open conformation. Jiang X, et al. Proc Natl Acad Sci U S A, 2016 Nov 1. PMID 27791182, Free PMC Article

    See all (179) citations in PubMed

    GeneRIFs: Gene References Into Functions

    What's a GeneRIF?
    1. Structural and Functional Adaptability of Sucrose and Lactose Permeases from Escherichia coli to the Membrane Lipid Composition.
      Title: Structural and Functional Adaptability of Sucrose and Lactose Permeases from Escherichia coli to the Membrane Lipid Composition.
    2. Diversity in kinetics correlated with structure in nano body-stabilized LacY.
      Title: Diversity in kinetics correlated with structure in nano body-stabilized LacY.
    3. Binding kinetics of alpha-galactopyranoside homologs with fluorescent aglycones of different sizes or shapes were determined with Escherichia coli LacY by FRET from Trp151 in the LacY binding site to the fluorophores. LacY specificity is directed toward the galactopyranoside ring. The pathway for the substrate entering from the periplasmic side is wider than the calculated pore diameters in periplasmic open X-ray struc...
      Title: Oversized galactosides as a probe for conformational dynamics in LacY.
    4. Glu325 exhibits a pKa of 10.5 +/- 0.1 that is insensitive to the presence of galactopyranoside. Protonation of Glu325 specifically is required for effective sugar binding to LacY
      Title: pK(a) of Glu325 in LacY.
    5. Data indicate that the nanobodies (Nbs) bind stoichiometrically with nanomolar affinity to the periplasmic face of lactose permease (LacY) primarily to the C-terminal six-helix bundle.
      Title: Crystal structure of a LacY-nanobody complex in a periplasmic-open conformation.
    6. studies suggest that a single carboxyl group in LacY (Glu325) may be the only side chain directly involved in H+ translocation and a carboxyl side chain with similar properties has been identified in FucP (Asp46) and XylE (Asp27), the present results imply that the pK of this residue is switched during H+/sugar symport in all three symporters.
      Title: pH Regulation of Electrogenic Sugar/H+ Symport in MFS Sugar Permeases.
    7. Molecular dynamics simulations indicated that the deprotonation of Glu325 induced the opening of the periplasmics side and partial closure of the cytoplasmic side of LacY, while protonation of the Glu269 caused a stable cross-domain salt-bridge (Glu130-Arg344) and completely closed the cytoplasmic side.
      Title: Coarse-grained simulations of proton-dependent conformational changes in lactose permease.
    8. The YidC prevents LacY from misfolding by stabilizing the unfolded state from which LacY inserts structural segments stepwise into the membrane until folding is completed. During stepwise insertion, YidC and the membrane together stabilize the transient folds.
      Title: YidC assists the stepwise and stochastic folding of membrane proteins.
    9. Double-replacement mutants of conserved Gly-Gly pairs bind galactoside with affinities 10-20-fold higher than that of the pseudo-WT or WT LacY. Moreover, site-directed alkylation of a periplasmic Cys replacement indicates that the periplasmic cavity becomes readily accessible in the double-replacement mutants.
      Title: Role of Conserved Gly-Gly Pairs on the Periplasmic Side of LacY.
    10. Studied conformational states and homology of LacY and XylE.
      Title: Conserved movement of TMS11 between occluded conformations of LacY and XylE of the major facilitator superfamily suggests a similar hinge-like mechanism.
    Submit: New GeneRIF Correction See all GeneRIFs (46)

    General gene information

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    Gene Ontology Provided by EcoCyc

    Function Evidence Code Pubs
    enables carbohydrate:proton symporter activity IDA
    Inferred from Direct Assay
    more info
    		 PubMed 
    enables carbohydrate:proton symporter activity IEA
    Inferred from Electronic Annotation
    more info
    		  
    enables lactose binding IBA
    Inferred from Biological aspect of Ancestor
    more info
    		  
    enables lactose binding IDA
    Inferred from Direct Assay
    more info
    		 PubMed 
    enables lactose:proton symporter activity IBA
    Inferred from Biological aspect of Ancestor
    more info
    		  
    enables lactose:proton symporter activity IDA
    Inferred from Direct Assay
    more info
    		 PubMed 
    enables lactose:proton symporter activity IMP
    Inferred from Mutant Phenotype
    more info
    		 PubMed 
    enables protein binding IPI
    Inferred from Physical Interaction
    more info
    		 PubMed 
    enables symporter activity IEA
    Inferred from Electronic Annotation
    more info
    		  
    enables transmembrane transporter activity IEA
    Inferred from Electronic Annotation
    more info
    		  
    Process Evidence Code Pubs
    involved_in carbohydrate transmembrane transport IEA
    Inferred from Electronic Annotation
    more info
    		  
    involved_in carbohydrate transport IEA
    Inferred from Electronic Annotation
    more info
    		  
    acts_upstream_of_or_within carbohydrate transport IMP
    Inferred from Mutant Phenotype
    more info
    		 PubMed 
    involved_in carbohydrate transport IMP
    Inferred from Mutant Phenotype
    more info
    		 PubMed 
    acts_upstream_of_or_within lactose transport IDA
    Inferred from Direct Assay
    more info
    		 PubMed 
    involved_in organic substance transport IBA
    Inferred from Biological aspect of Ancestor
    more info
    		  
    involved_in organic substance transport IEA
    Inferred from Electronic Annotation
    more info
    		  
    involved_in proton transmembrane transport IEA
    Inferred from Electronic Annotation
    more info
    		  
    involved_in transmembrane transport IEA
    Inferred from Electronic Annotation
    more info
    		  
    Component Evidence Code Pubs
    located_in membrane IDA
    Inferred from Direct Assay
    more info
    		 PubMed 
    located_in membrane IEA
    Inferred from Electronic Annotation
    more info
    		  
    is_active_in plasma membrane IBA
    Inferred from Biological aspect of Ancestor
    more info
    		  
    located_in plasma membrane IDA
    Inferred from Direct Assay
    more info
    		 PubMed 
    located_in plasma membrane IEA
    Inferred from Electronic Annotation
    more info
    		  

    General protein information

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    Preferred Names
    lactose permease

    NCBI Reference Sequences (RefSeq)

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    Genome Annotation

    The following sections contain reference sequences that belong to a specific genome build. Explain

    Reference assembly

    Genomic

    1. NC_000913.3 Reference assembly

      Range
      361926..363179 complement
      Download
      GenBank, FASTA, Sequence Viewer (Graphics)

    mRNA and Protein(s)

    1. NP_414877.1 lactose permease [Escherichia coli str. K-12 substr. MG1655]

      See identical proteins and their annotated locations for NP_414877.1

      Status: PROVISIONAL

      UniProtKB/TrEMBL
      A0A5B9AUY1
      Conserved Domains (1) summary
      pfam01306
      Location:1 → 413
      LacY_symp; LacY proton/sugar symporter
    Nucleotide Protein
    Heading Accession and Version

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