P68187 (MALK_ECOLI) Reviewed, UniProtKB/Swiss-Prot

Names and origin

Protein names

Recommended name:
Maltose/maltodextrin import ATP-binding protein MalK
EC=3.6.3.19

Gene names

Name:	malK
Ordered Locus Names:	b4035, JW3995

Organism

Escherichia coli (strain K12) [Reference proteome] [HAMAP]

Taxonomic identifier

83333 [NCBI]

Taxonomic lineage

cellular organisms › Bacteria › Proteobacteria › Gammaproteobacteria › Enterobacteriales › Enterobacteriaceae › Escherichia › Escherichia coli

Protein attributes

Sequence length	371 AA.
Sequence status	Complete.
Protein existence	Evidence at protein level

General annotation (Comments)

Function	Part of the ABC transporter complex MalEFGK involved in maltose/maltodextrin import. Responsible for energy coupling to the transport system.
Catalytic activity	ATP + H2O + maltose(Out) = ADP + phosphate + maltose(In).
Subunit structure	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. Ref.16
Subcellular location	Cell inner membrane; Peripheral membrane protein Ref.15 Ref.16.
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. 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.
Sequence similarities	Belongs to the ABC transporter superfamily. Maltooligosaccharide importer (TC 3.A.1.1.1) family. [View classification] Contains 1 ABC transporter domain.
Sequence caution	The sequence CAA23582.1 differs from that shown. Reason: Erroneous initiation. Translation N-terminally shortened.

Ontologies

Keywords
Biological process	Sugar transport Transport
Cellular component	Cell inner membrane Cell membrane Membrane
Ligand	ATP-binding Nucleotide-binding
Molecular function	Hydrolase
Technical term	3D-structure Complete proteome Reference proteome
Gene Ontology (GO)
Biological_process	maltodextrin transport Inferred from genetic interaction PubMed 6997044. Source: EcoCyc
Cellular_component	ATP-binding cassette (ABC) transporter complex Inferred from direct assay Ref.9. Source: EcoCyc plasma membrane Inferred from electronic annotation. Source: UniProtKB-SubCell
Molecular_function	ATP binding Inferred from electronic annotation. Source: UniProtKB-KW maltooligosaccharide-importing ATPase activity Inferred from genetic interaction PubMed 6997044. Source: EcoCyc maltose-transporting ATPase activity Inferred from direct assay Ref.9. Source: EcoCyc
Complete GO annotation...

Sequence annotation (Features)

Feature key

Position(s)

Length

Description

Graphical view

Feature identifier

Molecule processing

Chain

1 – 371

371

Maltose/maltodextrin import ATP-binding protein MalK

PRO_0000092475

Regions

Domain

4 – 234

231

ABC transporter

Nucleotide binding

36 – 43

8

ATP By similarity

Experimental info

Mutagenesis

85

1

A → M: Suppressor of EAA loop mutations in MalFG. Ref.12

Mutagenesis

106

1

K → C: Suppressor of EAA loop mutations in MalFG. Ref.13

Mutagenesis

114

1

V → C: Suppressor of EAA loop mutations in MalFG. Ref.13

Mutagenesis

117

1

V → M: Suppressor of EAA loop mutations in MalFG. Ref.12

Mutagenesis

119

1

E → K: Resistant to inhibitory effects of alpha-methylglucoside but retains transport capacity. Ref.10

Mutagenesis

124

1

A → T: Resistant to inhibitory effects of alpha-methylglucoside but retains transport capacity. Ref.8

Mutagenesis

137

1

G → A: Loss of maltose transport. Has greater ability to decrease mal gene expression than wild-type MalK. Ref.10

Mutagenesis

158

1

D → N: Loss of maltose transport but retains ability to repress mal genes. Ref.10

Mutagenesis

228

1

R → C: Resistant to inhibitory effects of alpha-methylglucoside but retains transport capacity. Ref.10

Mutagenesis

241

1

F → I: Resistant to inhibitory effects of alpha-methylglucoside but retains transport capacity. Ref.8

Mutagenesis

267

1

W → G: Normal maltose transport but constitutive mal gene expression. Ref.10

Mutagenesis

278

1

G → P: Resistant to inhibitory effects of alpha-methylglucoside but retains transport capacity. Ref.8

Mutagenesis

282

1

S → L: Resistant to inhibitory effects of alpha-methylglucoside but retains transport capacity. Ref.10

Mutagenesis

284

1

G → S: Resistant to inhibitory effects of alpha-methylglucoside but retains transport capacity. Ref.8

Mutagenesis

302

1

G → D: Resistant to inhibitory effects of alpha-methylglucoside but retains transport capacity. Ref.10

Mutagenesis

308

1

E → Q: Maltose transport is affected but retains ability to interact with MalT. Ref.14

Mutagenesis

322

1

S → F: Resistant to inhibitory effects of alpha-methylglucoside but retains transport capacity. Ref.10

Mutagenesis

340

1

G → A: Maltose transport is affected but retains ability to interact with MalT. Ref.14

Mutagenesis

346

1

G → S: Normal maltose transport but constitutive mal gene expression. Ref.10

Mutagenesis

355

1

F → Y: Maltose transport is affected but retains ability to interact with MalT. Ref.14

Sequence conflict

220 – 241

22

ELYHY…PKMNF → AVPLSGRPFCRRIYRFAKDE L in AAB59057. Ref.1

Secondary structure

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371

Helix Strand Turn

Details...

Beta strand

4 – 13

10

Beta strand

16 – 26

11

Beta strand

31 – 35

5

Helix

42 – 49

8

Beta strand

51 – 53

3

Beta strand

56 – 62

7

Helix

72 – 74

3

Beta strand

77 – 80

4

Turn

82 – 85

4

Beta strand

88 – 90

3

Helix

92 – 96

5

Helix

98 – 102

5

Helix

107 – 120

14

Helix

124 – 126

3

Helix

131 – 133

3

Helix

136 – 150

15

Beta strand

153 – 159

7

Turn

160 – 163

4

Helix

166 – 183

18

Beta strand

186 – 190

5

Helix

194 – 200

7

Beta strand

202 – 208

7

Beta strand

211 – 216

6

Helix

218 – 223

6

Helix

228 – 233

6

Beta strand

234 – 237

4

Beta strand

240 – 249

10

Beta strand

254 – 257

4

Helix

261 – 263

3

Beta strand

265 – 270

6

Beta strand

280 – 285

6

Turn

287 – 289

3

Helix

293 – 295

3

Beta strand

297 – 309

13

Beta strand

311 – 319

9

Beta strand

323 – 325

3

Beta strand

327 – 333

7

Beta strand

342 – 346

5

Helix

349 – 351

3

Beta strand

353 – 355

3

Beta strand

359 – 361

3

Sequences

	Sequence		Length	Mass (Da)
	P68187 [UniParc]. Last modified October 25, 2004. Version 1. Checksum: 240D58F59450F30E	FASTA	371	40,990
	10 20 30 40 50 60 MASVQLQNVT KAWGEVVVSK DINLDIHEGE FVVFVGPSGC GKSTLLRMIA GLETITSGDL 70 80 90 100 110 120 FIGEKRMNDT PPAERGVGMV FQSYALYPHL SVAENMSFGL KLAGAKKEVI NQRVNQVAEV 130 140 150 160 170 180 LQLAHLLDRK PKALSGGQRQ RVAIGRTLVA EPSVFLLDEP LSNLDAALRV QMRIEISRLH 190 200 210 220 230 240 KRLGRTMIYV THDQVEAMTL ADKIVVLDAG RVAQVGKPLE LYHYPADRFV AGFIGSPKMN 250 260 270 280 290 300 FLPVKVTATA IDQVQVELPM PNRQQVWLPV ESRDVQVGAN MSLGIRPEHL LPSDIADVIL 310 320 330 340 350 360 EGEVQVVEQL GNETQIHIQI PSIRQNLVYR QNDVVLVEEG ATFAIGLPPE RCHLFREDGT 370 ACRRLHKEPG V

References

	« Hide 'large scale' referencesShow 'large scale' references »
[1]	"Sequence of the malK gene in E.coli K12." Gilson E., Nikaido H., Hofnung M. Nucleic Acids Res. 10:7449-7458(1982) [PubMed] [Europe PMC] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA]. Strain: K12.
[2]	"Comparison of sequences from the malB regions of Salmonella typhimurium and Enterobacter aerogenes with Escherichia coli K12: a potential new regulatory site in the interoperonic region." Dahl M.K., Francoz E., Saurin W., Boos W., Manson M.D., Hofnung M. Mol. Gen. Genet. 218:199-207(1989) [PubMed] [Europe PMC] [Abstract] Cited for: SEQUENCE REVISION.
[3]	"Analysis of the Escherichia coli genome. IV. DNA sequence of the region from 89.2 to 92.8 minutes." Blattner F.R., Burland V.D., Plunkett G. III, Sofia H.J., Daniels D.L. Nucleic Acids Res. 21:5408-5417(1993) [PubMed] [Europe PMC] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA]. Strain: K12 / MG1655 / ATCC 47076.
[4]	"The complete genome sequence of Escherichia coli K-12." Blattner F.R., Plunkett G. III, Bloch C.A., Perna N.T., Burland V., Riley M., Collado-Vides J., Glasner J.D., Rode C.K., Mayhew G.F., Gregor J., Davis N.W., Kirkpatrick H.A., Goeden M.A., Rose D.J., Mau B., Shao Y. Science 277:1453-1474(1997) [PubMed] [Europe PMC] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA]. Strain: K12 / MG1655 / ATCC 47076.
[5]	"Highly accurate genome sequences of Escherichia coli K-12 strains MG1655 and W3110." Hayashi K., Morooka N., Yamamoto Y., Fujita K., Isono K., Choi S., Ohtsubo E., Baba T., Wanner B.L., Mori H., Horiuchi T. Mol. Syst. Biol. 2:E1-E5(2006) [PubMed] [Europe PMC] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA]. Strain: K12 / W3110 / ATCC 27325 / DSM 5911.
[6]	"A DNA sequence containing the control regions of the malEFG and malK-lamB operons in Escherichia coli K12." Bedouelle H., Hofnung M. Mol. Gen. Genet. 185:82-87(1982) [PubMed] [Europe PMC] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA] OF 1-30.
[7]	"Overproduction, solubilization, and reconstitution of the maltose transport system from Escherichia coli." Davidson A.L., Nikaido H. J. Biol. Chem. 265:4254-4260(1990) [PubMed] [Europe PMC] [Abstract] Cited for: CHARACTERIZATION OF MALTOSE TRANSPORT AND ATP HYDROLYSIS ACTIVITIES.
[8]	"Regulation of the maltose transport system of Escherichia coli by the glucose-specific enzyme III of the phosphoenolpyruvate-sugar phosphotransferase system. Characterization of inducer exclusion-resistant mutants and reconstitution of inducer exclusion in proteoliposomes." Dean D.A., Reizer J., Nikaido H., Saier M.H. Jr. J. Biol. Chem. 265:21005-21010(1990) [PubMed] [Europe PMC] [Abstract] Cited for: REGULATION, MUTAGENESIS OF ALA-124; PHE-241; GLY-278 AND GLY-284.
[9]	"Purification and characterization of the membrane-associated components of the maltose transport system from Escherichia coli." Davidson A.L., Nikaido H. J. Biol. Chem. 266:8946-8951(1991) [PubMed] [Europe PMC] [Abstract] Cited for: PURIFICATION OF THE MALK-MALF-MALG COMPLEX AND ITS ATPASE ACTIVITY.
[10]	"The activities of the Escherichia coli MalK protein in maltose transport, regulation, and inducer exclusion can be separated by mutations." Kuehnau S., Reyes M., Sievertsen A., Shuman H.A., Boos W. J. Bacteriol. 173:2180-2186(1991) [PubMed] [Europe PMC] [Abstract] Cited for: REGULATION, MUTAGENESIS OF GLU-119; GLY-137; ASP-158; ARG-228; TRP-267; SER-282; GLY-302; SER-322 AND GLY-346.
[11]	"The ATP-binding cassette subunit of the maltose transporter MalK antagonizes MalT, the activator of the Escherichia coli mal regulon." Panagiotidis C.H., Boos W., Shuman H.A. Mol. Microbiol. 30:535-546(1998) [PubMed] [Europe PMC] [Abstract] Cited for: INTERACTION BETWEEN MALK AND MALT.
[12]	"Subunit interactions in ABC transporters: a conserved sequence in hydrophobic membrane proteins of periplasmic permeases defines an important site of interaction with the ATPase subunits." Mourez M., Hofnung M., Dassa E. EMBO J. 16:3066-3077(1997) [PubMed] [Europe PMC] [Abstract] Cited for: MUTAGENESIS OF ALA-85 AND VAL-117.
[13]	"ATP modulates subunit-subunit interactions in an ATP-binding cassette transporter (MalFGK2) determined by site-directed chemical cross-linking." Hunke S., Mourez M., Jehanno M., Dassa E., Schneider E. J. Biol. Chem. 275:15526-15534(2000) [PubMed] [Europe PMC] [Abstract] Cited for: MUTAGENESIS OF LYS-106 AND VAL-114.
[14]	"Structural model of MalK, the ABC subunit of the maltose transporter of Escherichia coli: implications for mal gene regulation, inducer exclusion, and subunit assembly." Boehm A., Diez J., Diederichs K., Welte W., Boos W. J. Biol. Chem. 277:3708-3717(2002) [PubMed] [Europe PMC] [Abstract] Cited for: MUTAGENESIS OF GLU-308; GLY-340 AND PHE-355, MODELING.
[15]	"Protein complexes of the Escherichia coli cell envelope." Stenberg F., Chovanec P., Maslen S.L., Robinson C.V., Ilag L., von Heijne G., Daley D.O. J. Biol. Chem. 280:34409-34419(2005) [PubMed] [Europe PMC] [Abstract] Cited for: SUBCELLULAR LOCATION. Strain: BL21-DE3.
[16]	"Biogenesis of MalF and the MalFGK(2) maltose transport complex in Escherichia coli requires YidC." Wagner S., Pop O.I., Haan G.J., Baars L., Koningstein G., Klepsch M.M., Genevaux P., Luirink J., de Gier J.W. J. Biol. Chem. 283:17881-17890(2008) [PubMed] [Europe PMC] [Abstract] Cited for: SUBUNIT, SUBCELLULAR LOCATION, REQUIREMENT FOR YIDC FOR PROTEIN AND COMPLEX FORMATION.
[17]	"Maltose/maltodextrin system of Escherichia coli: transport, metabolism, and regulation." Boos W., Shuman H. Microbiol. Mol. Biol. Rev. 62:204-229(1998) [PubMed] [Europe PMC] [Abstract] Cited for: REVIEW.
[18]	"Import of solutes by ABC transporters - The maltose and other systems." Schneider E. (In) Holland I.B., Cole S.P.C., Kuchler K., Higgins C.F. (eds.); ABC proteins from bacteria to man, pp.157-185, Academic Press, San Diego. (2003) Cited for: REVIEW.
[19]	"A tweezers-like motion of the ATP-binding cassette dimer in an ABC transport cycle." Chen J., Lu G., Lin J., Davidson A.L., Quiocho F.A. Mol. Cell 12:651-661(2003) [PubMed] [Europe PMC] [Abstract] Cited for: X-RAY CRYSTALLOGRAPHY (2.6 ANGSTROMS).
+	Additional computationally mapped references.

Cross-references

Sequence databases

EMBL
GenBank
DDBJ

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.

PIR

MMECMK. B65211.

RefSeq

NP_418459.1. NC_000913.2.
YP_492178.1. NC_007779.1.

3D structure databases

PDBe
RCSB PDB
PDBj

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	[»]

ProteinModelPortal

P68187.

SMR

P68187. Positions 2-371.

ModBase

Search...

Protein-protein interaction databases

DIP

DIP-47850N.

IntAct

P68187. 6 interactions.

MINT

MINT-1223477.

STRING

511145.b4035.

Protein family/group databases

TCDB

3.A.1.1.1. ATP-binding cassette (ABC) superfamily.

Proteomic databases

PaxDb

P68187.

Protocols and materials databases

StructuralBiologyKnowledgebase

Search...

Genome annotation databases

EnsemblBacteria

AAC77005; AAC77005; b4035.
BAE78037; BAE78037; BAE78037.

GeneID

12933668.
948537.

KEGG

ecj:Y75_p3922.
eco:b4035.

PATRIC

32123603. VBIEscCol129921_4150.

Organism-specific databases

EchoBASE

EB0553.

EcoGene

EG10558. malK.

Phylogenomic databases

eggNOG

COG3839.

KO

K10111.

OMA

ETQIYIQ.

ProtClustDB

PRK11000.

Enzyme and pathway databases

BioCyc

EcoCyc:MALK-MONOMER.
ECOL316407:JW3995-MONOMER.

Gene expression databases

Genevestigator

P68187.

Family and domain databases

Gene3D

2.40.50.140. 1 hit.

InterPro

IPR003593. AAA+_ATPase.
IPR003439. ABC_transporter-like.
IPR017871. ABC_transporter_CS.
IPR015855. ABC_transpr_MalK.
IPR008995. Mo/tungstate-bd_C_term_dom.
IPR012340. NA-bd_OB-fold.
IPR027417. P-loop_NTPase.
IPR013611. Transp-assoc_OB_typ2.
[Graphical view]

Pfam

PF00005. ABC_tran. 1 hit.
PF08402. TOBE_2. 1 hit.
[Graphical view]

SMART

SM00382. AAA. 1 hit.
[Graphical view]

SUPFAM

SSF50331. MOP_like. 1 hit.
SSF52540. SSF52540. 1 hit.

PROSITE

PS00211. ABC_TRANSPORTER_1. 1 hit.
PS50893. ABC_TRANSPORTER_2. 1 hit.
PS51245. MALK. 1 hit.
[Graphical view]

ProtoNet

Search...

Other

EvolutionaryTrace

P68187.

Entry information

Entry name

MALK_ECOLI

Accession

Primary (citable) accession number: P68187
Secondary accession number(s): P02914, Q2M6R9, Q47348

Entry history

Integrated into UniProtKB/Swiss-Prot:	July 21, 1986
Last sequence update:	October 25, 2004
Last modified:	May 29, 2013
This is version 96 of the entry and version 1 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation program

Prokaryotic Protein Annotation Program