UniProtKB - P02943 (LAMB_ECOLI)
Maltoporin
lamB
Functioni
Involved in the transport of maltose and maltodextrins (PubMed:3301537, PubMed:2832377, PubMed:11742115, PubMed:7824948, PubMed:8805519, PubMed:9299337).
Indispensable for translocation of maltodextrins (alpha 1-4 linked polyglucosyls) 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 (PubMed:7824948, PubMed:8805519, PubMed:9299337, PubMed:11742115).
Also acts as a receptor for several bacteriophages including lambda (PubMed:4201774).
Binds maltosaccharides; when LamB binds starch in soft agar, it inhibits motility (PubMed:2832377).
7 PublicationsSites
Feature key | Position(s) | DescriptionActions | Graphical view | Length |
---|---|---|---|---|
Sitei | 31 | Greasy slide, important in sugar transportUniRule annotation2 Publications | 1 | |
Sitei | 66 | Greasy slide, important in sugar transportUniRule annotation2 Publications | 1 | |
Sitei | 99 | Greasy slide, important in sugar transportUniRule annotation2 Publications | 1 | |
Sitei | 143 | Important in sugar transportUniRule annotation1 Publication | 1 | |
Sitei | 252 | Greasy slide, important in sugar transportUniRule annotation2 Publications | 1 | |
Sitei | 383 | Greasy slide, important in sugar transportUniRule annotation2 Publications | 1 | |
Sitei | 445 | Greasy slide, important in sugar transportUniRule annotation2 Publications | 1 |
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
- polysaccharide transport Source: GO_Central
Keywordsi
Molecular function | Host cell receptor for virus entry, Porin, Receptor |
Biological process | Host-virus interaction, Ion transport, Sugar transport, Transport |
Enzyme and pathway databases
BioCyci | EcoCyc:EG10528-MONOMER |
Protein family/group databases
TCDBi | 1.B.3.1.1, the sugar porin (sp) family |
Names & Taxonomyi
Protein namesi | Recommended name: MaltoporinUniRule annotationAlternative name(s): Maltose outer membrane channelCurated Maltose-inducible porinUniRule annotation Phage lambda receptor protein1 Publication |
Gene namesi | Name:lamBUniRule annotation Synonyms:malB Ordered Locus Names:b4036, JW3996 |
Organismi | Escherichia coli (strain K12) |
Taxonomic identifieri | 83333 [NCBI] |
Taxonomic lineagei | Bacteria › Proteobacteria › Gammaproteobacteria › Enterobacterales › Enterobacteriaceae › Escherichia › |
Proteomesi |
|
Subcellular locationi
Other locations
- Cell outer membrane UniRule annotation4 Publications; Multi-pass membrane protein UniRule annotation1 Publication
Other locations
- cell outer membrane Source: EcoCyc
- integral component of cell outer membrane Source: EcoCyc
- pore complex Source: EcoCyc
Topology
Feature key | Position(s) | DescriptionActions | Graphical view | Length |
---|---|---|---|---|
Topological domaini | 26 | Periplasmic | 1 | |
Transmembranei | 27 – 40 | Beta strandedAdd BLAST | 14 | |
Topological domaini | 41 – 64 | Extracellular1 PublicationAdd BLAST | 24 | |
Transmembranei | 65 – 75 | Beta strandedAdd BLAST | 11 | |
Topological domaini | 76 – 81 | Periplasmic1 Publication | 6 | |
Transmembranei | 82 – 93 | Beta strandedAdd BLAST | 12 | |
Topological domaini | 94 – 104 | Extracellular1 PublicationAdd BLAST | 11 | |
Transmembranei | 105 – 115 | Beta strandedAdd BLAST | 11 | |
Topological domaini | 116 – 122 | Periplasmic1 Publication | 7 | |
Transmembranei | 123 – 130 | Beta stranded | 8 | |
Topological domaini | 131 – 156 | Extracellular1 PublicationAdd BLAST | 26 | |
Transmembranei | 157 – 159 | Beta stranded | 3 | |
Topological domaini | 160 – 161 | Periplasmic1 Publication | 2 | |
Transmembranei | 162 – 173 | Beta strandedAdd BLAST | 12 | |
Topological domaini | 174 – 191 | Extracellular1 PublicationAdd BLAST | 18 | |
Transmembranei | 192 – 204 | Beta strandedAdd BLAST | 13 | |
Topological domaini | 205 – 208 | Periplasmic1 Publication | 4 | |
Transmembranei | 209 – 222 | Beta strandedAdd BLAST | 14 | |
Topological domaini | 223 – 234 | Extracellular1 PublicationAdd BLAST | 12 | |
Transmembranei | 235 – 248 | Beta strandedAdd BLAST | 14 | |
Topological domaini | 249 – 250 | Periplasmic1 Publication | 2 | |
Transmembranei | 251 – 263 | Beta strandedAdd BLAST | 13 | |
Topological domaini | 264 – 290 | Extracellular1 PublicationAdd BLAST | 27 | |
Transmembranei | 291 – 305 | Beta strandedAdd BLAST | 15 | |
Topological domaini | 306 – 307 | Periplasmic1 Publication | 2 | |
Transmembranei | 308 – 323 | Beta strandedAdd BLAST | 16 | |
Topological domaini | 324 – 326 | Extracellular1 Publication | 3 | |
Transmembranei | 327 – 341 | Beta strandedAdd BLAST | 15 | |
Topological domaini | 342 – 344 | Periplasmic1 Publication | 3 | |
Transmembranei | 345 – 359 | Beta strandedAdd BLAST | 15 | |
Topological domaini | 360 – 362 | Extracellular1 Publication | 3 | |
Transmembranei | 363 – 376 | Beta strandedAdd BLAST | 14 | |
Topological domaini | 377 – 386 | Periplasmic1 Publication | 10 | |
Transmembranei | 387 – 399 | Beta strandedAdd BLAST | 13 | |
Topological domaini | 400 – 430 | Extracellular1 PublicationAdd BLAST | 31 | |
Transmembranei | 431 – 445 | Beta strandedAdd BLAST | 15 | |
Topological domaini | 446 | Periplasmic | 1 |
Keywords - Cellular componenti
Cell outer membrane, MembranePathology & Biotechi
Disruption phenotypei
Mutagenesis
Feature key | Position(s) | DescriptionActions | Graphical view | Length |
---|---|---|---|---|
Mutagenesisi | 33 | R → H in lamB1040; reduces ligand affinity and pore size, no longer selective for maltodextrins. Reduced starch binding, grows on maltodextrins, no change in phage lambda binding. 2 Publications | 1 | |
Mutagenesisi | 34 | S → SGS in lamB375; decreased protein at 37 but not 30 degrees Celsius, reduced starch binding, no growth on dextrins, decreased affinity for maltose, loss of phage lambda binding. 1 Publication | 1 | |
Mutagenesisi | 47 | C → S: Normal transport activity, assembled trimer is less stable. 1 Publication | 1 | |
Mutagenesisi | 63 | C → S: Normal transport activity, assembled trimer is less stable. 1 Publication | 1 | |
Mutagenesisi | 99 | W → R: Decreases starch affinity, slightly increases maltose affinity. 1 Publication | 1 | |
Mutagenesisi | 104 | P → PDP in lamB147; decreased affinity for maltose, grows on maltodextrins, no change in phage lambda binding. 1 Publication | 1 | |
Mutagenesisi | 107 | R → S: Decreases maltodextrin affinity, increases sucrose binding and transport. 1 Publication | 1 | |
Mutagenesisi | 134 | R → A: Considerable increase in pore size and sucrose transport, slight decrease in maltose transport; when associated with A-143. 1 Publication | 1 | |
Mutagenesisi | 134 | R → 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 Publication | 1 | |
Mutagenesisi | 143 | Y → F: Increases affinity for starch and maltose, pore size and transport of maltohexaose. 2 Publications | 1 | |
Mutagenesisi | 143 | Y → YY in lamB203; reduced starch binding, no maltose transport, no growth on dextrins, decreased protein in outer membrane at 37 but not 30 degrees Celsius, no change in phage lambda binding. 1 Publication | 1 | |
Mutagenesisi | 146 | D → G: Increases affinity for large dextrins. 2 Publications | 1 | |
Mutagenesisi | 219 | G → D in lamB1002; decreased affinity for maltose, loss of phage lambda binding. 1 Publication | 1 | |
Mutagenesisi | 385 | R → C in lamb1004; reduced starch binding, decreased affinity for maltose, no change in phage lambda binding. 1 Publication | 1 | |
Mutagenesisi | 386 | P → PDP in lamB146; loss of starch binding, grows poorly on maltodextrins, reduced affinity for somaltose. 1 Publication | 1 | |
Mutagenesisi | 445 – 446 | Missing in lamB1007; significantly less protein in outer membrane, no growth on dextrins, reduced susceptibility to phage lambda. 1 Publication | 2 |
Chemistry databases
DrugBanki | DB02379, Beta-D-Glucose DB04173, Fructose |
PTM / Processingi
Molecule processing
Feature key | Position(s) | DescriptionActions | Graphical view | Length |
---|---|---|---|---|
Signal peptidei | 1 – 25 | 1 PublicationAdd BLAST | 25 | |
ChainiPRO_0000025175 | 26 – 446 | MaltoporinUniRule annotationAdd BLAST | 421 |
Amino acid modifications
Feature key | Position(s) | DescriptionActions | Graphical view | Length |
---|---|---|---|---|
Disulfide bondi | 47 ↔ 63 | 1 Publication1 Publication |
Keywords - PTMi
Disulfide bondProteomic databases
jPOSTi | P02943 |
PaxDbi | P02943 |
PRIDEi | P02943 |
Expressioni
Inductioni
Interactioni
Subunit structurei
Homotrimer formed of three 18-stranded antiparallel beta-barrels, containing three independent channels (PubMed:1988451, PubMed:16079137, PubMed:7824948, PubMed:8805519, PubMed:9299337) (By similarity). An intrasubunit disulfide bond contributes to trimer stability (PubMed:1988451).
UniRule annotation5 PublicationsBinary interactionsi
P02943
With | #Exp. | IntAct |
---|---|---|
secA [P10408] | 3 | EBI-371309,EBI-543213 |
Protein-protein interaction databases
BioGRIDi | 4262663, 259 interactors |
DIPi | DIP-10082N |
IntActi | P02943, 3 interactors |
STRINGi | 511145.b4036 |
Structurei
Secondary structure
3D structure databases
SMRi | P02943 |
ModBasei | Search... |
PDBe-KBi | Search... |
Miscellaneous databases
EvolutionaryTracei | P02943 |
Family & Domainsi
Sequence similaritiesi
Keywords - Domaini
Signal, Transmembrane, Transmembrane beta strandPhylogenomic databases
eggNOGi | COG4580, Bacteria |
HOGENOMi | CLU_032473_4_1_6 |
PhylomeDBi | P02943 |
Family and domain databases
CDDi | cd01346, Maltoporin-like, 1 hit |
Gene3Di | 2.40.170.10, 1 hit |
HAMAPi | MF_01301, LamB, 1 hit |
InterProi | View protein in InterPro IPR023738, Maltoporin IPR003192, Porin_LamB IPR036998, Porin_LamB_sf |
Pfami | View protein in Pfam PF02264, LamB, 1 hit |
i Sequence
Sequence statusi: Complete.
: The displayed sequence is further processed into a mature form. Sequence processingi
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
Experimental Info
Feature key | Position(s) | DescriptionActions | Graphical view | Length |
---|---|---|---|---|
Sequence conflicti | 381 | S → T in AAC43130 (PubMed:8265357).Curated | 1 |
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 |
PIRi | A03443, QRECL |
RefSeqi | NP_418460.1, NC_000913.3 WP_000973663.1, NZ_SSZK01000016.1 |
Genome annotation databases
EnsemblBacteriai | AAC77006; AAC77006; b4036 BAE78038; BAE78038; BAE78038 |
GeneIDi | 948548 |
KEGGi | ecj:JW3996 eco:b4036 |
PATRICi | fig|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 |
PIRi | A03443, QRECL |
RefSeqi | NP_418460.1, NC_000913.3 WP_000973663.1, NZ_SSZK01000016.1 |
3D structure databases
Select the link destinations: PDBei RCSB PDBi PDBji Links Updated | PDB entry | Method | Resolution (Å) | Chain | Positions | PDBsum |
1AF6 | X-ray | 2.40 | A/B/C | 26-446 | [»] | |
1MAL | X-ray | 3.10 | A/B/C | 26-446 | [»] | |
1MPM | X-ray | 2.60 | A/B/C | 26-446 | [»] | |
1MPN | X-ray | 3.20 | A/B/C | 26-446 | [»] | |
1MPO | X-ray | 2.80 | A/B/C | 26-446 | [»] | |
1MPQ | X-ray | 3.00 | A/B/C | 26-446 | [»] | |
SMRi | P02943 | |||||
ModBasei | Search... | |||||
PDBe-KBi | Search... |
Protein-protein interaction databases
BioGRIDi | 4262663, 259 interactors |
DIPi | DIP-10082N |
IntActi | P02943, 3 interactors |
STRINGi | 511145.b4036 |
Chemistry databases
DrugBanki | DB02379, Beta-D-Glucose DB04173, Fructose |
Protein family/group databases
TCDBi | 1.B.3.1.1, the sugar porin (sp) family |
Proteomic databases
jPOSTi | P02943 |
PaxDbi | P02943 |
PRIDEi | P02943 |
Genome annotation databases
EnsemblBacteriai | AAC77006; AAC77006; b4036 BAE78038; BAE78038; BAE78038 |
GeneIDi | 948548 |
KEGGi | ecj:JW3996 eco:b4036 |
PATRICi | fig|1411691.4.peg.2674 |
Organism-specific databases
EchoBASEi | EB0523 |
Phylogenomic databases
eggNOGi | COG4580, Bacteria |
HOGENOMi | CLU_032473_4_1_6 |
PhylomeDBi | P02943 |
Enzyme and pathway databases
BioCyci | EcoCyc:EG10528-MONOMER |
Miscellaneous databases
EvolutionaryTracei | P02943 |
PROi | PR:P02943 |
Family and domain databases
CDDi | cd01346, Maltoporin-like, 1 hit |
Gene3Di | 2.40.170.10, 1 hit |
HAMAPi | MF_01301, LamB, 1 hit |
InterProi | View protein in InterPro IPR023738, Maltoporin IPR003192, Porin_LamB IPR036998, Porin_LamB_sf |
Pfami | View protein in Pfam PF02264, LamB, 1 hit |
MobiDBi | Search... |
Entry informationi
Entry namei | LAMB_ECOLI | |
Accessioni | P02943Primary (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: | February 23, 2022 | |
This is version 202 of the entry and version 1 of the sequence. See complete history. | ||
Entry statusi | Reviewed (UniProtKB/Swiss-Prot) | |
Annotation program | Prokaryotic Protein Annotation Program |
Miscellaneousi
Keywords - Technical termi
3D-structure, Direct protein sequencing, Reference proteomeDocuments
- PDB cross-references
Index of Protein Data Bank (PDB) cross-references - SIMILARITY comments
Index of protein domains and families