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Protein

Maltoporin

Gene

lamB

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

Functioni

Involved in the transport of maltose and maltodextrins, indispensable for translocation of dextrins containing more than three glucosyl moieties. A hydrophobic path ("greasy slide") of aromatic residues serves to guide and select the sugars for transport through the channel. Also acts as a receptor for several bacteriophages including lambda.

Sites

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Sitei31Greasy slide, important in sugar transport1
Sitei66Greasy slide, important in sugar transport1
Sitei99Greasy slide, important in sugar transport1
Sitei143Important in sugar transport1
Sitei252Greasy slide, important in sugar transport1
Sitei383Greasy slide, important in sugar transport1
Sitei445Greasy slide, important in sugar transport1

GO - Molecular functioni

  • carbohydrate transmembrane transporter activity Source: GO_Central
  • maltodextrin transmembrane transporter activity Source: EcoCyc
  • maltose transporting porin activity Source: InterPro
  • porin activity Source: CACAO
  • virus receptor activity Source: UniProtKB-KW

GO - Biological processi

  • cellular response to DNA damage stimulus Source: EcoliWiki
  • ion transport Source: UniProtKB-KW
  • maltodextrin transport Source: EcoCyc

Keywordsi

Molecular functionHost cell receptor for virus entry, Porin, Receptor
Biological processHost-virus interaction, Ion transport, Sugar transport, Transport

Enzyme and pathway databases

BioCyciEcoCyc:EG10528-MONOMER
MetaCyc:EG10528-MONOMER

Protein family/group databases

TCDBi1.B.3.1.1 the sugar porin (sp) family

Names & Taxonomyi

Protein namesi
Recommended name:
Maltoporin
Alternative name(s):
Lambda receptor protein
Maltose-inducible porin
Gene namesi
Name:lamB
Synonyms:malB
Ordered Locus Names:b4036, JW3996
OrganismiEscherichia coli (strain K12)
Taxonomic identifieri83333 [NCBI]
Taxonomic lineageiBacteriaProteobacteriaGammaproteobacteriaEnterobacteralesEnterobacteriaceaeEscherichia
Proteomesi
  • UP000000318 Componenti: Chromosome
  • UP000000625 Componenti: Chromosome

Organism-specific databases

EcoGeneiEG10528 lamB

Subcellular locationi

Topology

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Topological domaini26Periplasmic1
Transmembranei27 – 35Beta stranded9
Topological domaini36 – 64ExtracellularAdd BLAST29
Transmembranei65 – 78Beta strandedAdd BLAST14
Topological domaini79 – 80Periplasmic2
Transmembranei81 – 93Beta strandedAdd BLAST13
Topological domaini94 – 104ExtracellularAdd BLAST11
Transmembranei105 – 115Beta strandedAdd BLAST11
Topological domaini116 – 122Periplasmic7
Transmembranei123 – 130Beta stranded8
Topological domaini131 – 148ExtracellularAdd BLAST18
Transmembranei149 – 159Beta strandedAdd BLAST11
Topological domaini160 – 161Periplasmic2
Transmembranei162 – 173Beta strandedAdd BLAST12
Topological domaini174 – 191ExtracellularAdd BLAST18
Transmembranei192 – 205Beta strandedAdd BLAST14
Topological domaini206 – 209Periplasmic4
Transmembranei210 – 222Beta strandedAdd BLAST13
Topological domaini223 – 234ExtracellularAdd BLAST12
Transmembranei235 – 248Beta strandedAdd BLAST14
Topological domaini249 – 250Periplasmic2
Transmembranei251 – 263Beta strandedAdd BLAST13
Topological domaini264 – 290ExtracellularAdd BLAST27
Transmembranei291 – 305Beta strandedAdd BLAST15
Topological domaini306 – 307Periplasmic2
Transmembranei308 – 323Beta strandedAdd BLAST16
Topological domaini324 – 326Extracellular3
Transmembranei327 – 341Beta strandedAdd BLAST15
Topological domaini342 – 343Periplasmic2
Transmembranei344 – 359Beta strandedAdd BLAST16
Topological domaini360 – 362Extracellular3
Transmembranei363 – 378Beta strandedAdd BLAST16
Topological domaini379 – 385Periplasmic7
Transmembranei386 – 400Beta strandedAdd BLAST15
Topological domaini401 – 430ExtracellularAdd BLAST30
Transmembranei431 – 445Beta strandedAdd BLAST15
Topological domaini446Periplasmic1

GO - Cellular componenti

Keywords - Cellular componenti

Cell outer membrane, Membrane

Pathology & Biotechi

Mutagenesis

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Mutagenesisi33R → H: Reduces ligand affinity and pore size, no longer selective for maltodextrins. 1 Publication1
Mutagenesisi99W → R: Decreases starch affinity, slightly increases maltose affinity. 1 Publication1
Mutagenesisi107R → S: Decreases maltodextrin affinity, increases sucrose binding and transport. 1 Publication1
Mutagenesisi134R → A: Considerable increase in pore size and sucrose transport, slight decrease in maltose transport; when associated with A-143. 1 Publication1
Mutagenesisi134R → D or N: Slight increase in pore size; increase in sucrose transport and slight decrease in maltose transport; when associated with D-143 and F-146. 1 Publication1
Mutagenesisi143Y → F: Increases affinity for starch and maltose, pore size and transport of maltohexaose. 2 Publications1
Mutagenesisi146D → G: Increases affinity for large dextrins. 2 Publications1

Chemistry databases

DrugBankiDB02379 Beta-D-Glucose
DB04173 Fructose

PTM / Processingi

Molecule processing

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Signal peptidei1 – 25Add BLAST25
ChainiPRO_000002517526 – 446MaltoporinAdd BLAST421

Amino acid modifications

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Disulfide bondi47 ↔ 631 Publication

Keywords - PTMi

Disulfide bond

Proteomic databases

PaxDbiP02943
PRIDEiP02943

Expressioni

Inductioni

By maltose.

Interactioni

Subunit structurei

Homotrimer formed of three 18-stranded antiparallel beta-barrels, containing three independent channels.1 Publication

Binary interactionsi

WithEntry#Exp.IntActNotes
secAP104083EBI-371309,EBI-543213

Protein-protein interaction databases

BioGridi4262663, 259 interactors
DIPiDIP-10082N
IntActiP02943, 3 interactors
STRINGi316385.ECDH10B_4225

Structurei

Secondary structure

1446
Legend: HelixTurnBeta strandPDB Structure known for this area
Show more details

3D structure databases

ProteinModelPortaliP02943
SMRiP02943
ModBaseiSearch...
MobiDBiSearch...

Miscellaneous databases

EvolutionaryTraceiP02943

Family & Domainsi

Sequence similaritiesi

Keywords - Domaini

Signal, Transmembrane, Transmembrane beta strand

Phylogenomic databases

eggNOGiENOG4108KDD Bacteria
COG4580 LUCA
HOGENOMiHOG000218083
KOiK02024

Family and domain databases

CDDicd01346 Maltoporin-like, 1 hit
Gene3Di2.40.170.10, 1 hit
HAMAPiMF_01301 LamB, 1 hit
InterProiView protein in InterPro
IPR023738 Maltoporin
IPR003192 Porin_LamB
IPR036998 Porin_LamB_sf
PfamiView protein in Pfam
PF02264 LamB, 1 hit
ProDomiView protein in ProDom or Entries sharing at least one domain
PD008788 Porin_LamB, 1 hit

Sequencei

Sequence statusi: Complete.

Sequence processingi: The displayed sequence is further processed into a mature form.

P02943-1 [UniParc]FASTAAdd to basket
« Hide
        10         20         30         40         50
MMITLRKLPL AVAVAAGVMS AQAMAVDFHG YARSGIGWTG SGGEQQCFQT
60 70 80 90 100
TGAQSKYRLG NECETYAELK LGQEVWKEGD KSFYFDTNVA YSVAQQNDWE
110 120 130 140 150
ATDPAFREAN VQGKNLIEWL PGSTIWAGKR FYQRHDVHMI DFYYWDISGP
160 170 180 190 200
GAGLENIDVG FGKLSLAATR SSEAGGSSSF ASNNIYDYTN ETANDVFDVR
210 220 230 240 250
LAQMEINPGG TLELGVDYGR ANLRDNYRLV DGASKDGWLF TAEHTQSVLK
260 270 280 290 300
GFNKFVVQYA TDSMTSQGKG LSQGSGVAFD NEKFAYNINN NGHMLRILDH
310 320 330 340 350
GAISMGDNWD MMYVGMYQDI NWDNDNGTKW WTVGIRPMYK WTPIMSTVME
360 370 380 390 400
IGYDNVESQR TGDKNNQYKI TLAQQWQAGD SIWSRPAIRV FATYAKWDEK
410 420 430 440
WGYDYTGNAD NNANFGKAVP ADFNGGSFGR GDSDEWTFGA QMEIWW
Length:446
Mass (Da):49,912
Last modified:July 21, 1986 - v1
Checksum:iB2D4E4F120DA494E
GO

Experimental Info

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Sequence conflicti35G → GSG (PubMed:2832377).Curated1
Sequence conflicti208P → PDP (PubMed:2832377).Curated1
Sequence conflicti381S → T in AAC43130 (PubMed:8265357).Curated1
Sequence conflicti385R → RDP (PubMed:2832377).Curated1

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
M16643 Genomic DNA Translation: AAA24059.1
M26131 Genomic DNA Translation: AAA24060.1
V00298 Genomic DNA Translation: CAA23575.1
J01648 Genomic DNA Translation: AAB59058.1
U00006 Genomic DNA Translation: AAC43130.1
U00096 Genomic DNA Translation: AAC77006.1
AP009048 Genomic DNA Translation: BAE78038.1
M24997 Genomic DNA Translation: AAC41396.1
V00297 Genomic DNA Translation: CAA23574.1
PIRiA03443 QRECL
RefSeqiNP_418460.1, NC_000913.3
WP_000973663.1, NZ_LN832404.1

Genome annotation databases

EnsemblBacteriaiAAC77006; AAC77006; b4036
BAE78038; BAE78038; BAE78038
GeneIDi948548
KEGGiecj:JW3996
eco:b4036
PATRICifig|1411691.4.peg.2674

Similar proteinsi

Cross-referencesi

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
M16643 Genomic DNA Translation: AAA24059.1
M26131 Genomic DNA Translation: AAA24060.1
V00298 Genomic DNA Translation: CAA23575.1
J01648 Genomic DNA Translation: AAB59058.1
U00006 Genomic DNA Translation: AAC43130.1
U00096 Genomic DNA Translation: AAC77006.1
AP009048 Genomic DNA Translation: BAE78038.1
M24997 Genomic DNA Translation: AAC41396.1
V00297 Genomic DNA Translation: CAA23574.1
PIRiA03443 QRECL
RefSeqiNP_418460.1, NC_000913.3
WP_000973663.1, NZ_LN832404.1

3D structure databases

Select the link destinations:
PDBei
RCSB PDBi
PDBji
Links Updated
PDB entryMethodResolution (Å)ChainPositionsPDBsum
1AF6X-ray2.40A/B/C26-446[»]
1MALX-ray3.10A/B/C26-446[»]
1MPMX-ray2.60A/B/C26-446[»]
1MPNX-ray3.20A/B/C26-446[»]
1MPOX-ray2.80A/B/C26-446[»]
1MPQX-ray3.00A/B/C26-446[»]
ProteinModelPortaliP02943
SMRiP02943
ModBaseiSearch...
MobiDBiSearch...

Protein-protein interaction databases

BioGridi4262663, 259 interactors
DIPiDIP-10082N
IntActiP02943, 3 interactors
STRINGi316385.ECDH10B_4225

Chemistry databases

DrugBankiDB02379 Beta-D-Glucose
DB04173 Fructose

Protein family/group databases

TCDBi1.B.3.1.1 the sugar porin (sp) family

Proteomic databases

PaxDbiP02943
PRIDEiP02943

Protocols and materials databases

Structural Biology KnowledgebaseSearch...

Genome annotation databases

EnsemblBacteriaiAAC77006; AAC77006; b4036
BAE78038; BAE78038; BAE78038
GeneIDi948548
KEGGiecj:JW3996
eco:b4036
PATRICifig|1411691.4.peg.2674

Organism-specific databases

EchoBASEiEB0523
EcoGeneiEG10528 lamB

Phylogenomic databases

eggNOGiENOG4108KDD Bacteria
COG4580 LUCA
HOGENOMiHOG000218083
KOiK02024

Enzyme and pathway databases

BioCyciEcoCyc:EG10528-MONOMER
MetaCyc:EG10528-MONOMER

Miscellaneous databases

EvolutionaryTraceiP02943
PROiPR:P02943

Family and domain databases

CDDicd01346 Maltoporin-like, 1 hit
Gene3Di2.40.170.10, 1 hit
HAMAPiMF_01301 LamB, 1 hit
InterProiView protein in InterPro
IPR023738 Maltoporin
IPR003192 Porin_LamB
IPR036998 Porin_LamB_sf
PfamiView protein in Pfam
PF02264 LamB, 1 hit
ProDomiView protein in ProDom or Entries sharing at least one domain
PD008788 Porin_LamB, 1 hit
ProtoNetiSearch...

Entry informationi

Entry nameiLAMB_ECOLI
AccessioniPrimary (citable) accession number: P02943
Secondary accession number(s): Q2M6R8
Entry historyiIntegrated into UniProtKB/Swiss-Prot: July 21, 1986
Last sequence update: July 21, 1986
Last modified: November 7, 2018
This is version 180 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

Documents

  1. SIMILARITY comments
    Index of protein domains and families
  2. PDB cross-references
    Index of Protein Data Bank (PDB) cross-references
  3. Escherichia coli
    Escherichia coli (strain K12): entries and cross-references to EcoGene
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Main funding by: National Institutes of Health

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