UniProtKB - P68187 (MALK_ECOLI)
Protein
Maltose/maltodextrin import ATP-binding protein MalK
Gene
malK
Organism
Escherichia coli (strain K12)
Status
Functioni
Part of the ABC transporter complex MalEFGK involved in maltose/maltodextrin import. Responsible for energy coupling to the transport system.2 Publications
Miscellaneous
Target for inducer exclusion, mediated by the unphosphorylated enzyme III of the phosphotransferase system for glucose and resulting in the inhibition of maltose transport.1 Publication
Acts as a repressor of mal genes. In absence of maltose, the C-terminus of MalK interacts with MalT, then MalT becomes inactive and the mal genes are not activated. In presence of maltose, MalK is tightly associated with the MalFG complex and has no affinity for MalT.1 Publication
Catalytic activityi
- EC:7.5.2.1UniRule annotation2 Publications
Regions
Feature key | Position(s) | DescriptionActions | Graphical view | Length |
---|---|---|---|---|
Nucleotide bindingi | 36 – 43 | ATPUniRule annotation | 8 |
GO - Molecular functioni
- ABC-type maltose transporter activity Source: EcoCyc
- activating transcription factor binding Source: EcoCyc
- ATPase activity Source: InterPro
- ATP binding Source: EcoCyc
GO - Biological processi
- maltodextrin transport Source: EcoCyc
- maltose transport Source: EcoCyc
Keywordsi
Molecular function | Translocase |
Biological process | Sugar transport, Transport |
Ligand | ATP-binding, Nucleotide-binding |
Enzyme and pathway databases
BioCyci | EcoCyc:MALK-MONOMER MetaCyc:MALK-MONOMER |
BRENDAi | 3.6.3.19, 2026 |
Protein family/group databases
MoonProti | P68187 |
TCDBi | 3.A.1.1.1, the atp-binding cassette (abc) superfamily |
Names & Taxonomyi
Protein namesi | Recommended name: Maltose/maltodextrin import ATP-binding protein MalKUniRule annotation (EC:7.5.2.1UniRule annotation2 Publications) |
Gene namesi | Name:malK1 PublicationUniRule annotation Ordered Locus Names:b4035, JW3995 |
Organismi | Escherichia coli (strain K12) |
Taxonomic identifieri | 83333 [NCBI] |
Taxonomic lineagei | Bacteria › Proteobacteria › Gammaproteobacteria › Enterobacterales › Enterobacteriaceae › Escherichia › |
Proteomesi |
|
Subcellular locationi
Plasma membrane
- Cell inner membrane UniRule annotation2 Publications; Peripheral membrane protein UniRule annotation2 Publications
Plasma Membrane
- ATP-binding cassette (ABC) transporter complex Source: EcoCyc
- ATP-binding cassette (ABC) transporter complex, substrate-binding subunit-containing Source: GO_Central
- extrinsic component of cytoplasmic side of plasma membrane Source: EcoCyc
- maltose transport complex Source: EcoCyc
Other locations
- membrane Source: UniProtKB
Keywords - Cellular componenti
Cell inner membrane, Cell membrane, MembranePathology & Biotechi
Mutagenesis
Feature key | Position(s) | DescriptionActions | Graphical view | Length |
---|---|---|---|---|
Mutagenesisi | 85 | A → M: Suppressor of EAA loop mutations in MalFG. 1 Publication | 1 | |
Mutagenesisi | 106 | K → C: Suppressor of EAA loop mutations in MalFG. 1 Publication | 1 | |
Mutagenesisi | 114 | V → C: Suppressor of EAA loop mutations in MalFG. 1 Publication | 1 | |
Mutagenesisi | 117 | V → M: Suppressor of EAA loop mutations in MalFG. 1 Publication | 1 | |
Mutagenesisi | 119 | E → K: Resistant to inhibitory effects of alpha-methylglucoside but retains transport capacity. 1 Publication | 1 | |
Mutagenesisi | 124 | A → T: Resistant to inhibitory effects of alpha-methylglucoside but retains transport capacity. 1 Publication | 1 | |
Mutagenesisi | 137 | G → A: Loss of maltose transport. Has greater ability to decrease mal gene expression than wild-type MalK. 1 Publication | 1 | |
Mutagenesisi | 158 | D → N: Loss of maltose transport but retains ability to repress mal genes. 1 Publication | 1 | |
Mutagenesisi | 228 | R → C: Resistant to inhibitory effects of alpha-methylglucoside but retains transport capacity. 1 Publication | 1 | |
Mutagenesisi | 241 | F → I: Resistant to inhibitory effects of alpha-methylglucoside but retains transport capacity. 1 Publication | 1 | |
Mutagenesisi | 267 | W → G: Normal maltose transport but constitutive mal gene expression. 1 Publication | 1 | |
Mutagenesisi | 278 | G → P: Resistant to inhibitory effects of alpha-methylglucoside but retains transport capacity. 1 Publication | 1 | |
Mutagenesisi | 282 | S → L: Resistant to inhibitory effects of alpha-methylglucoside but retains transport capacity. 1 Publication | 1 | |
Mutagenesisi | 284 | G → S: Resistant to inhibitory effects of alpha-methylglucoside but retains transport capacity. 1 Publication | 1 | |
Mutagenesisi | 302 | G → D: Resistant to inhibitory effects of alpha-methylglucoside but retains transport capacity. 1 Publication | 1 | |
Mutagenesisi | 308 | E → Q: Maltose transport is affected but retains ability to interact with MalT. 1 Publication | 1 | |
Mutagenesisi | 322 | S → F: Resistant to inhibitory effects of alpha-methylglucoside but retains transport capacity. 1 Publication | 1 | |
Mutagenesisi | 340 | G → A: Maltose transport is affected but retains ability to interact with MalT. 1 Publication | 1 | |
Mutagenesisi | 346 | G → S: Normal maltose transport but constitutive mal gene expression. 1 Publication | 1 | |
Mutagenesisi | 355 | F → Y: Maltose transport is affected but retains ability to interact with MalT. 1 Publication | 1 |
PTM / Processingi
Molecule processing
Feature key | Position(s) | DescriptionActions | Graphical view | Length |
---|---|---|---|---|
ChainiPRO_0000092475 | 1 – 371 | Maltose/maltodextrin import ATP-binding protein MalKAdd BLAST | 371 |
Proteomic databases
jPOSTi | P68187 |
PaxDbi | P68187 |
PRIDEi | P68187 |
Interactioni
Subunit structurei
The complex is composed of two ATP-binding proteins (MalK), two transmembrane proteins (MalG and MalF) and a solute-binding protein (MalE). Protein stability and stable complex formation require YidC.
3 PublicationsGO - Molecular functioni
- activating transcription factor binding Source: EcoCyc
Protein-protein interaction databases
BioGRIDi | 4262662, 20 interactors |
ComplexPortali | CPX-1932, Maltose ABC transporter complex CPX-1978, Enzyme IIA-maltose transport inhibitory complex |
DIPi | DIP-47850N |
IntActi | P68187, 8 interactors |
STRINGi | 511145.b4035 |
Structurei
Secondary structure
Legend: HelixTurnBeta strandPDB Structure known for this area
Show more details3D structure databases
SMRi | P68187 |
ModBasei | Search... |
PDBe-KBi | Search... |
Miscellaneous databases
EvolutionaryTracei | P68187 |
Family & Domainsi
Domains and Repeats
Feature key | Position(s) | DescriptionActions | Graphical view | Length |
---|---|---|---|---|
Domaini | 4 – 234 | ABC transporterUniRule annotationAdd BLAST | 231 |
Sequence similaritiesi
Belongs to the ABC transporter superfamily. Maltooligosaccharide importer (TC 3.A.1.1.1) family. [View classification]UniRule annotation
Phylogenomic databases
eggNOGi | COG3842, Bacteria |
HOGENOMi | CLU_000604_1_1_6 |
InParanoidi | P68187 |
PhylomeDBi | P68187 |
Family and domain databases
InterProi | View protein in InterPro IPR003593, AAA+_ATPase IPR003439, ABC_transporter-like IPR017871, ABC_transporter_CS IPR015855, ABC_transpr_MalK IPR008995, Mo/tungstate-bd_C_term_dom IPR040582, OB_MalK IPR027417, P-loop_NTPase |
Pfami | View protein in Pfam PF00005, ABC_tran, 1 hit PF17912, OB_MalK, 1 hit |
SMARTi | View protein in SMART SM00382, AAA, 1 hit |
SUPFAMi | SSF50331, SSF50331, 1 hit SSF52540, SSF52540, 1 hit |
PROSITEi | View protein in PROSITE PS00211, ABC_TRANSPORTER_1, 1 hit PS50893, ABC_TRANSPORTER_2, 1 hit PS51245, MALK, 1 hit |
i Sequence
Sequence statusi: Complete.
P68187-1 [UniParc]FASTAAdd to basket
10 20 30 40 50
MASVQLQNVT KAWGEVVVSK DINLDIHEGE FVVFVGPSGC GKSTLLRMIA
60 70 80 90 100
GLETITSGDL FIGEKRMNDT PPAERGVGMV FQSYALYPHL SVAENMSFGL
110 120 130 140 150
KLAGAKKEVI NQRVNQVAEV LQLAHLLDRK PKALSGGQRQ RVAIGRTLVA
160 170 180 190 200
EPSVFLLDEP LSNLDAALRV QMRIEISRLH KRLGRTMIYV THDQVEAMTL
210 220 230 240 250
ADKIVVLDAG RVAQVGKPLE LYHYPADRFV AGFIGSPKMN FLPVKVTATA
260 270 280 290 300
IDQVQVELPM PNRQQVWLPV ESRDVQVGAN MSLGIRPEHL LPSDIADVIL
310 320 330 340 350
EGEVQVVEQL GNETQIHIQI PSIRQNLVYR QNDVVLVEEG ATFAIGLPPE
360 370
RCHLFREDGT ACRRLHKEPG V
Sequence cautioni
The sequence CAA23582 differs from that shown. Reason: Erroneous initiation. Extended N-terminus.Curated
Experimental Info
Feature key | Position(s) | DescriptionActions | Graphical view | Length |
---|---|---|---|---|
Sequence conflicti | 220 – 241 | ELYHY…PKMNF → AVPLSGRPFCRRIYRFAKDE L in AAB59057 (PubMed:6296778).CuratedAdd BLAST | 22 |
Sequence databases
Select the link destinations: EMBLi GenBanki DDBJi Links Updated | J01648 Genomic DNA Translation: AAB59057.1 U00006 Genomic DNA Translation: AAC43129.1 U00096 Genomic DNA Translation: AAC77005.1 AP009048 Genomic DNA Translation: BAE78037.1 V00303 Genomic DNA Translation: CAA23582.1 Different initiation. |
PIRi | B65211, MMECMK |
RefSeqi | NP_418459.1, NC_000913.3 WP_000179165.1, NZ_STEB01000022.1 |
Genome annotation databases
EnsemblBacteriai | AAC77005; AAC77005; b4035 BAE78037; BAE78037; BAE78037 |
GeneIDi | 57730531 948537 |
KEGGi | ecj:JW3995 eco:b4035 |
PATRICi | fig|511145.12.peg.4150 |
Similar proteinsi
Cross-referencesi
Sequence databases
Select the link destinations: EMBLi GenBanki DDBJi Links Updated | J01648 Genomic DNA Translation: AAB59057.1 U00006 Genomic DNA Translation: AAC43129.1 U00096 Genomic DNA Translation: AAC77005.1 AP009048 Genomic DNA Translation: BAE78037.1 V00303 Genomic DNA Translation: CAA23582.1 Different initiation. |
PIRi | B65211, MMECMK |
RefSeqi | NP_418459.1, NC_000913.3 WP_000179165.1, NZ_STEB01000022.1 |
3D structure databases
Select the link destinations: PDBei RCSB PDBi PDBji Links Updated | PDB entry | Method | Resolution (Å) | Chain | Positions | PDBsum |
1Q12 | X-ray | 2.60 | A/B/C/D | 1-371 | [»] | |
1Q1B | X-ray | 2.80 | A/B/C/D | 1-371 | [»] | |
1Q1E | X-ray | 2.90 | A/B | 1-371 | [»] | |
2AWN | X-ray | 2.30 | A/B/C/D | 1-371 | [»] | |
2AWO | X-ray | 2.80 | A/B/C/D | 1-371 | [»] | |
2R6G | X-ray | 2.80 | A/B | 1-371 | [»] | |
3FH6 | X-ray | 4.50 | A/B/C/D | 1-371 | [»] | |
3GD7 | X-ray | 2.70 | A/B/C/D | 219-371 | [»] | |
3PUV | X-ray | 2.40 | A/B | 1-371 | [»] | |
3PUW | X-ray | 2.30 | A/B | 1-371 | [»] | |
3PUX | X-ray | 2.30 | A/B | 1-371 | [»] | |
3PUY | X-ray | 3.10 | A/B | 1-371 | [»] | |
3PUZ | X-ray | 2.90 | A/B | 1-371 | [»] | |
3PV0 | X-ray | 3.10 | A/B | 1-371 | [»] | |
3RLF | X-ray | 2.20 | A/B | 1-371 | [»] | |
4JBW | X-ray | 3.91 | A/B/C/D | 1-371 | [»] | |
4KI0 | X-ray | 2.38 | A/B | 1-371 | [»] | |
SMRi | P68187 | |||||
ModBasei | Search... | |||||
PDBe-KBi | Search... |
Protein-protein interaction databases
BioGRIDi | 4262662, 20 interactors |
ComplexPortali | CPX-1932, Maltose ABC transporter complex CPX-1978, Enzyme IIA-maltose transport inhibitory complex |
DIPi | DIP-47850N |
IntActi | P68187, 8 interactors |
STRINGi | 511145.b4035 |
Protein family/group databases
MoonProti | P68187 |
TCDBi | 3.A.1.1.1, the atp-binding cassette (abc) superfamily |
Proteomic databases
jPOSTi | P68187 |
PaxDbi | P68187 |
PRIDEi | P68187 |
Genome annotation databases
EnsemblBacteriai | AAC77005; AAC77005; b4035 BAE78037; BAE78037; BAE78037 |
GeneIDi | 57730531 948537 |
KEGGi | ecj:JW3995 eco:b4035 |
PATRICi | fig|511145.12.peg.4150 |
Organism-specific databases
EchoBASEi | EB0553 |
Phylogenomic databases
eggNOGi | COG3842, Bacteria |
HOGENOMi | CLU_000604_1_1_6 |
InParanoidi | P68187 |
PhylomeDBi | P68187 |
Enzyme and pathway databases
BioCyci | EcoCyc:MALK-MONOMER MetaCyc:MALK-MONOMER |
BRENDAi | 3.6.3.19, 2026 |
Miscellaneous databases
EvolutionaryTracei | P68187 |
PROi | PR:P68187 |
Family and domain databases
InterProi | View protein in InterPro IPR003593, AAA+_ATPase IPR003439, ABC_transporter-like IPR017871, ABC_transporter_CS IPR015855, ABC_transpr_MalK IPR008995, Mo/tungstate-bd_C_term_dom IPR040582, OB_MalK IPR027417, P-loop_NTPase |
Pfami | View protein in Pfam PF00005, ABC_tran, 1 hit PF17912, OB_MalK, 1 hit |
SMARTi | View protein in SMART SM00382, AAA, 1 hit |
SUPFAMi | SSF50331, SSF50331, 1 hit SSF52540, SSF52540, 1 hit |
PROSITEi | View protein in PROSITE PS00211, ABC_TRANSPORTER_1, 1 hit PS50893, ABC_TRANSPORTER_2, 1 hit PS51245, MALK, 1 hit |
ProtoNeti | Search... |
MobiDBi | Search... |
Entry informationi
Entry namei | MALK_ECOLI | |
Accessioni | P68187Primary (citable) accession number: P68187 Secondary accession number(s): P02914, Q2M6R9, Q47348 | |
Entry historyi | Integrated into UniProtKB/Swiss-Prot: | July 21, 1986 |
Last sequence update: | October 25, 2004 | |
Last modified: | April 7, 2021 | |
This is version 156 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, Reference proteomeDocuments
- PDB cross-references
Index of Protein Data Bank (PDB) cross-references - SIMILARITY comments
Index of protein domains and families