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Protein

Maltoporin

Gene

lamB

Organism
Escherichia coli (strain K12)
Status
Reviewed-Annotation score: Annotation score: 5 out of 5-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

  • 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
Complete GO annotation...

Keywords - Molecular functioni

Host cell receptor for virus entry, Porin, Receptor

Keywords - Biological processi

Host-virus interaction, Ion transport, Sugar transport, Transport

Enzyme and pathway databases

BioCyciEcoCyc:EG10528-MONOMER.
ECOL316407:JW3996-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

  • cell outer membrane Source: EcoCyc
  • integral component of cell outer membrane Source: EcoCyc
  • pore complex Source: EcoCyc
Complete GO annotation...

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

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. 252 interactors.
DIPiDIP-10082N.
IntActiP02943. 2 interactors.
STRINGi511145.b4036.

Structurei

Secondary structure

1446
Legend: HelixTurnBeta strandPDB Structure known for this area
Show more details
Feature keyPosition(s)DescriptionActionsGraphical viewLength
Beta strandi27 – 39Combined sources13
Beta strandi42 – 44Combined sources3
Beta strandi64 – 78Combined sources15
Beta strandi81 – 93Combined sources13
Beta strandi95 – 98Combined sources4
Beta strandi105 – 115Combined sources11
Beta strandi118 – 120Combined sources3
Beta strandi124 – 130Combined sources7
Beta strandi135 – 137Combined sources3
Helixi138 – 140Combined sources3
Beta strandi142 – 145Combined sources4
Beta strandi149 – 158Combined sources10
Beta strandi160 – 180Combined sources21
Helixi185 – 187Combined sources3
Beta strandi190 – 207Combined sources18
Beta strandi210 – 221Combined sources12
Beta strandi236 – 248Combined sources13
Beta strandi251 – 261Combined sources11
Helixi262 – 264Combined sources3
Turni265 – 267Combined sources3
Beta strandi277 – 279Combined sources3
Beta strandi285 – 287Combined sources3
Beta strandi292 – 305Combined sources14
Turni306 – 308Combined sources3
Beta strandi309 – 322Combined sources14
Beta strandi328 – 358Combined sources31
Turni359 – 361Combined sources3
Beta strandi364 – 381Combined sources18
Beta strandi387 – 403Combined sources17
Turni409 – 411Combined sources3
Turni413 – 416Combined sources4
Beta strandi418 – 420Combined sources3
Helixi423 – 425Combined sources3
Beta strandi432 – 446Combined sources15

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...

Miscellaneous databases

EvolutionaryTraceiP02943.

Family & Domainsi

Sequence similaritiesi

Keywords - Domaini

Signal, Transmembrane, Transmembrane beta strand

Phylogenomic databases

eggNOGiENOG4108KDD. Bacteria.
COG4580. LUCA.
HOGENOMiHOG000218083.
KOiK02024.
OMAiYNKFVLQ.

Family and domain databases

CDDicd01346. Maltoporin-like. 1 hit.
Gene3Di2.40.170.10. 1 hit.
HAMAPiMF_01301. LamB. 1 hit.
InterProiIPR023738. Maltoporin.
IPR003192. Porin_LamB.
[Graphical view]
PfamiPF02264. LamB. 1 hit.
[Graphical view]
ProDomiPD008788. Porin_LamB. 1 hit.
[Graphical view] [Entries sharing at least one domain]

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.
PATRICi32123605. VBIEscCol129921_4151.

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. 252 interactors.
DIPiDIP-10082N.
IntActiP02943. 2 interactors.
STRINGi511145.b4036.

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.
PATRICi32123605. VBIEscCol129921_4151.

Organism-specific databases

EchoBASEiEB0523.
EcoGeneiEG10528. lamB.

Phylogenomic databases

eggNOGiENOG4108KDD. Bacteria.
COG4580. LUCA.
HOGENOMiHOG000218083.
KOiK02024.
OMAiYNKFVLQ.

Enzyme and pathway databases

BioCyciEcoCyc:EG10528-MONOMER.
ECOL316407:JW3996-MONOMER.
MetaCyc:EG10528-MONOMER.

Miscellaneous databases

EvolutionaryTraceiP02943.
PROiP02943.

Family and domain databases

CDDicd01346. Maltoporin-like. 1 hit.
Gene3Di2.40.170.10. 1 hit.
HAMAPiMF_01301. LamB. 1 hit.
InterProiIPR023738. Maltoporin.
IPR003192. Porin_LamB.
[Graphical view]
PfamiPF02264. LamB. 1 hit.
[Graphical view]
ProDomiPD008788. Porin_LamB. 1 hit.
[Graphical view] [Entries sharing at least one domain]
ProtoNetiSearch...

Entry informationi

Entry nameiLAMB_ECOLI
AccessioniPrimary (citable) accession number: P02943
Secondary accession number(s): Q2M6R8
Entry historyi
Integrated into UniProtKB/Swiss-Prot: July 21, 1986
Last sequence update: July 21, 1986
Last modified: November 30, 2016
This is version 172 of the entry and version 1 of the sequence. [Complete history]
Entry statusiReviewed (UniProtKB/Swiss-Prot)
Annotation programProkaryotic Protein Annotation Program

Miscellaneousi

Keywords - Technical termi

3D-structure, Complete proteome, Reference proteome

Documents

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

Similar proteinsi

Links to similar proteins from the UniProt Reference Clusters (UniRef) at 100%, 90% and 50% sequence identity:
100%UniRef100 combines identical sequences and sub-fragments with 11 or more residues from any organism into one UniRef entry.
90%UniRef90 is built by clustering UniRef100 sequences that have at least 90% sequence identity to, and 80% overlap with, the longest sequence (a.k.a seed sequence).
50%UniRef50 is built by clustering UniRef90 seed sequences that have at least 50% sequence identity to, and 80% overlap with, the longest sequence in the cluster.