Escherichia coli K-12 substr. MG1655 Enzyme: tetraacyldisaccharide 4'-kinase

Gene: lpxK Accession Numbers: EG11409 (EcoCyc), b0915, ECK0906

Synonyms: ycaH

Regulation Summary Diagram: ?

Regulation summary diagram for lpxK

Tetraacyldisaccharide 4'-kinase (LpxK) catalyzes the sixth step in lipid A biosynthesis. LpxK transfers a phosphate from ATP to the 4' position of a tetraacyldisaccharide1-phosphate intermediate to form tetraacyldisaccharide 1,4'-bis-phosphate (lipid IVA). The reaction requires Mg2+ and is stimulated by phospholipids. Though it can function with all nucleotide triphosphates, the enzymatic reaction is most efficient with ATP [Ray87, Garrett97, Garrett98].

LpxK is an integral membrane protein, which contains predicted membrane-spanning segments at its N-terminus. Most of the LpxK sedimented with the membrane pellet rather than the cell free extract. [Ray87]

lpxK is an essential gene, which cotranscribes with msbA [Garrett98]. msbA is also an essential gene which codes for a transport protein that brings lipid A from the inner membrane to the outer membrane [Karow93].

LpxK from Aquifex aeolicus has been characterized. The crystal structure of LpxK from Aquifex aeolicus shows an N-terminal domain that is responsible for catalysis at the P-loop and positioning of the disaccharide-1-phosphate substrate for phosphoryl transfer on the inner membrane. The C-terminal domain helps bind the nucleotide substrate and Mg2+ cation. The kinetic activity was reported and active site residues identified. [Emptage12, Emptage13]

Citations: [Hampton92]

Locations: cytosol, inner membrane

Map Position: [967,589 -> 968,575] (20.85 centisomes, 75°)
Length: 987 bp / 328 aa

Molecular Weight of Polypeptide: 35.589 kD (from nucleotide sequence)

Unification Links: ASAP:ABE-0003115 , DIP:DIP-10126N , EchoBASE:EB1381 , EcoGene:EG11409 , EcoliWiki:b0915 , OU-Microarray:b0915 , PortEco:lpxK , PR:PRO_000023125 , Pride:P27300 , Protein Model Portal:P27300 , RefSeq:NP_415435 , RegulonDB:EG11409 , SMR:P27300 , String:511145.b0915 , UniProt:P27300

Relationship Links: InterPro:IN-FAMILY:IPR003758 , InterPro:IN-FAMILY:IPR027417 , Pfam:IN-FAMILY:PF02606

Gene-Reaction Schematic: ?

Gene-Reaction Schematic

GO Terms:

Biological Process: GO:0009244 - lipopolysaccharide core region biosynthetic process Inferred from experiment [Garrett98]
GO:0009245 - lipid A biosynthetic process Inferred from experiment Inferred by computational analysis [UniProtGOA11a, GOA06, GOA01a, Garrett97, Garrett98]
GO:0006629 - lipid metabolic process Inferred by computational analysis [UniProtGOA11a]
GO:0016310 - phosphorylation Inferred by computational analysis [UniProtGOA11a]
Molecular Function: GO:0009029 - tetraacyldisaccharide 4'-kinase activity Inferred from experiment Inferred by computational analysis [GOA06, GOA01, GOA01a, Garrett98, Garrett97]
GO:0016301 - kinase activity Inferred from experiment Inferred by computational analysis [UniProtGOA11a, Garrett97]
GO:0000166 - nucleotide binding Inferred by computational analysis [UniProtGOA11a]
GO:0005524 - ATP binding Inferred by computational analysis [UniProtGOA11a, GOA06, GOA01a]
GO:0016740 - transferase activity Inferred by computational analysis [UniProtGOA11a]
Cellular Component: GO:0005886 - plasma membrane Inferred from experiment [Garrett97]
GO:0016020 - membrane Inferred from experiment [Garrett97]
GO:0005829 - cytosol Inferred by computational analysis [DiazMejia09]

MultiFun Terms: cell structure capsule (M and K antigens)
cell structure membrane
cell structure murein
cell structure surface antigens (ECA, O antigen of LPS)
metabolism biosynthesis of macromolecules (cellular constituents) K antigen
metabolism biosynthesis of macromolecules (cellular constituents) lipopolysaccharide core region
metabolism biosynthesis of macromolecules (cellular constituents) lipopolysaccharide lipid A

Essentiality data for lpxK knockouts: ?

Growth Medium Growth? T (°C) O2 pH Osm/L Growth Observations
LB Lennox No 37 Aerobic 7   No [Baba06, Comment 1]

Curated 24-Aug-2006 by Shearer A , SRI International
Last-Curated ? 24-Jul-2013 by Kubo A , SRI International

Enzymatic reaction of: tetraacyldisaccharide 4'-kinase

Synonyms: lipid-A 4'-kinase, ATP:2,3,2',3'-tetrakis(3-hydroxytetradecanoyl)-D-glucosaminyl-β-D-1, 6-glucosaminyl-β-phosphate 4'-O-phosphotransferase

EC Number:

lipid A disaccharide + ATP <=> lipid IVA + ADP + H+

The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the direction in which it was curated.

The reaction is favored in the direction shown.

Alternative Substrates for ATP: GTP [Ray87 ] , UTP [Ray87 ] , CTP [Ray87 ]

In Pathways: superpathway of (Kdo)2-lipid A biosynthesis , superpathway of lipopolysaccharide biosynthesis , lipid IVA biosynthesis

Cofactors or Prosthetic Groups: Mg2+ [Ray87]

Activators (Unknown Mechanism): a cardiolipin [Ray87]

Sequence Features

Protein sequence of tetraacyldisaccharide 4'-kinase with features indicated

Feature Class Location Citations Comment
Nucleotide-Phosphate-Binding-Region 55 -> 62
UniProt: ATP; Non-Experimental Qualifier: potential;
Sequence-Conflict 158
[Karow93, UniProt10]
UniProt: (in Ref. 1; CAA77840);

Gene Local Context (not to scale): ?

Gene local context diagram

Transcription Unit:

Transcription-unit diagram


10/20/97 Gene b0915 from Blattner lab Genbank (v. M52) entry merged into EcoCyc gene EG11409; confirmed by SwissProt match.


Baba06: Baba T, Ara T, Hasegawa M, Takai Y, Okumura Y, Baba M, Datsenko KA, Tomita M, Wanner BL, Mori H (2006). "Construction of Escherichia coli K-12 in-frame, single-gene knockout mutants: the Keio collection." Mol Syst Biol 2;2006.0008. PMID: 16738554

DiazMejia09: Diaz-Mejia JJ, Babu M, Emili A (2009). "Computational and experimental approaches to chart the Escherichia coli cell-envelope-associated proteome and interactome." FEMS Microbiol Rev 33(1);66-97. PMID: 19054114

Emptage12: Emptage RP, Daughtry KD, Pemble CW, Raetz CR (2012). "Crystal structure of LpxK, the 4'-kinase of lipid A biosynthesis and atypical P-loop kinase functioning at the membrane interface." Proc Natl Acad Sci U S A 109(32);12956-61. PMID: 22826246

Emptage13: Emptage RP, Pemble CW, York JD, Raetz CR, Zhou P (2013). "Mechanistic characterization of the tetraacyldisaccharide-1-phosphate 4'-kinase LpxK involved in lipid A biosynthesis." Biochemistry 52(13);2280-90. PMID: 23464738

Garrett97: Garrett TA, Kadrmas JL, Raetz CR (1997). "Identification of the gene encoding the Escherichia coli lipid A 4'-kinase. Facile phosphorylation of endotoxin analogs with recombinant LpxK." J Biol Chem 1997;272(35);21855-64. PMID: 9268317

Garrett98: Garrett TA, Que NL, Raetz CR (1998). "Accumulation of a lipid A precursor lacking the 4'-phosphate following inactivation of the Escherichia coli lpxK gene." J Biol Chem 1998;273(20);12457-65. PMID: 9575203

GOA01: GOA, MGI (2001). "Gene Ontology annotation based on Enzyme Commission mapping." Genomics 74;121-128.

GOA01a: GOA, DDB, FB, MGI, ZFIN (2001). "Gene Ontology annotation through association of InterPro records with GO terms."

GOA06: GOA, SIB (2006). "Electronic Gene Ontology annotations created by transferring manual GO annotations between orthologous microbial proteins."

Hampton92: Hampton RY, Raetz CR (1992). "Lipid A 4'-kinase from Escherichia coli: enzyme assay and preparation of 4'-32P-labeled probes of high specific radioactivity." Methods Enzymol 1992;209;466-75. PMID: 1323052

Karow93: Karow M, Georgopoulos C (1993). "The essential Escherichia coli msbA gene, a multicopy suppressor of null mutations in the htrB gene, is related to the universally conserved family of ATP-dependent translocators." Mol Microbiol 7(1);69-79. PMID: 8094880

Ray87: Ray BL, Raetz CR (1987). "The biosynthesis of gram-negative endotoxin. A novel kinase in Escherichia coli membranes that incorporates the 4'-phosphate of lipid A." J Biol Chem 1987;262(3);1122-8. PMID: 3027079

UniProt10: UniProt Consortium (2010). "UniProt version 2010-11 released on 2010-11-02 00:00:00." Database.

UniProt10a: UniProt Consortium (2010). "UniProt version 2010-07 released on 2010-06-15 00:00:00." Database.

UniProtGOA11a: UniProt-GOA (2011). "Gene Ontology annotation based on manual assignment of UniProtKB keywords in UniProtKB/Swiss-Prot entries."

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Please cite the following article in publications resulting from the use of EcoCyc: Nucleic Acids Research 41:D605-12 2013
Page generated by SRI International Pathway Tools version 19.0 on Tue Oct 13, 2015, biocyc12.