Escherichia coli K-12 substr. MG1655 Enzyme: Kdo2-lipid A phosphotransferase

Gene: lpxT Accession Numbers: G7146 (EcoCyc), b2174, ECK2168

Synonyms: yeiU

Regulation Summary Diagram: ?

Regulation summary diagram for lpxT

LpxT is responsible for transfer of a phosphate group from undecaprenyl-pyrophosphate to the position 1 phosphate of approximately one-third of lipid A molecules to create lipid A 1-diphosphate. LpxT is one of four Und-PP pyrophosphatases in E. coli along with BacA, YbjG, and PgpB. Und-P acts as a carrier for glycan intermediates of carbohydrate polymers such as peptidoglycan, teichoic acids, enterobacterial common antigen, and O antigen. Und-PP must be converted to Und-P by an Und-PP pyrophosphatase in order to be used and reused for attachment of these glycan intermediates.

LpxT is a membrane protein with its C-terminus in the cytoplasm [Tatar07]. The catalytic acid phosphatase domain is located in the periplasm [Tatar07, Touze08].

In vitro assays show LpxT transfers a phosphate from Und-PP to Kdo2-lipid A [Touze08]. Bacitracin inhibited this reaction by sequestering Und-PP in vivo [Touze08]. Activation of the BasSR two-component system by Fe3+ results in the post-translational inhibition of LpxT-dependent lipid A modification [Herrera10].

lpxT mutants do not produce lipid A 1-diphosphate [Touze08]. The LpxT gene product appears to have a low level of undecaprenyl pyrophosphate (C55PP) phosphatase activity [El05]. Simultaneous inactivation of three genes encoding C55PP phosphatases, pgpB, bacA, and ybjG, is lethal [El05]. Depletion of BacA in the triple mutant strain causes changes in cell morphology and lysis [El05]. Overexpression of lpxT, pgpB, bacA, and ybjG leads to increased C55PP phosphatase activity in crude membrane extracts [El05]. Expression of C55PP phosphatase activity from any one of the three genes pgpB, bacA and ybjG appears to be sufficient for synthesis of undecaprenyl phosphate and survival, while expression of lpxT alone does not appear to be sufficient [El05]. bacA lpxT and bacA lpxT ybjG mutants have reduced survival in response to the inhibition of Und-PP synthesis by fosmidomycin [Tatar07]. A waaL bacA lpxT ybjG quadruple deletion mutant of W3110 expressing wbbL for O16 antigen production had increased levels of O16 attached to Und-PP resulting in a growth defect due to severely decreased availability of Und-P from recycling of Und-PP [Tatar07].

Expression of lpxT is increased by exposure to sodium salicylate [Pomposiello01]. Expression of lpxT was upregulated under basic conditions during anaerobic growth, and under acidic conditions during aerobic growth [Hayes06]. Expression of lpxT is repressed in biofilms in a tnaA mutant [Lee07].

Review: [Valvano08]

Locations: inner membrane

Map Position: [2,266,876 -> 2,267,589] (48.86 centisomes, 176°)
Length: 714 bp / 237 aa

Molecular Weight of Polypeptide: 26.759 kD (from nucleotide sequence)

Unification Links: ASAP:ABE-0007196 , EchoBASE:EB3828 , EcoGene:EG14075 , EcoliWiki:b2174 , ModBase:P76445 , OU-Microarray:b2174 , PortEco:lpxT , Protein Model Portal:P76445 , RefSeq:NP_416679 , RegulonDB:G7146 , String:511145.b2174 , UniProt:P76445

Relationship Links: InterPro:IN-FAMILY:IPR000326 , Pfam:IN-FAMILY:PF01569 , Smart:IN-FAMILY:SM00014

In Paralogous Gene Group: 211 (2 members)

Gene-Reaction Schematic: ?

Gene-Reaction Schematic

Genetic Regulation Schematic: ?

Genetic regulation schematic for lpxT

GO Terms:

Biological Process: GO:0043165 - Gram-negative-bacterium-type cell outer membrane assembly Inferred from experiment [Touze08]
GO:0009103 - lipopolysaccharide biosynthetic process Inferred by computational analysis [UniProtGOA12, UniProtGOA11a]
Molecular Function: GO:0016776 - phosphotransferase activity, phosphate group as acceptor Inferred from experiment [Touze08]
GO:0050380 - undecaprenyl-diphosphatase activity Inferred from experiment [Touze08]
GO:0003824 - catalytic activity Inferred by computational analysis [GOA01]
GO:0016740 - transferase activity Inferred by computational analysis [UniProtGOA11a]
Cellular Component: GO:0005886 - plasma membrane Inferred from experiment Inferred by computational analysis [UniProtGOA11, UniProtGOA11a, DiazMejia09, Zhang07, Daley05]
GO:0016020 - membrane Inferred by computational analysis [UniProtGOA11a, GOA01]
GO:0016021 - integral component of membrane Inferred by computational analysis [UniProtGOA11a]

MultiFun Terms: cell structure

Essentiality data for lpxT knockouts: ?

Growth Medium Growth? T (°C) O2 pH Osm/L Growth Observations
LB enriched Yes 37 Aerobic 6.95   Yes [Gerdes03, Comment 1]
LB Lennox Yes 37 Aerobic 7   Yes [Baba06, Comment 2]
M9 medium with 1% glycerol Yes 37 Aerobic 7.2 0.35 Yes [Joyce06, Comment 3]
MOPS medium with 0.4% glucose Yes 37 Aerobic 7.2 0.22 Yes [Baba06, Comment 2]

Last-Curated ? 30-May-2008 by Johnson A , JCVI

Enzymatic reaction of: Kdo2-lipid A phosphotransferase

EC Number:

α-D-Kdo-(2→4)-α-D-Kdo-(2→6)-lipid A + di-trans,octa-cis-undecaprenyl diphosphate <=> α-D-Kdo-(2→4)-α-D-Kdo-(2→6)-lipid A 1-diphosphate + di-trans,octa-cis-undecaprenyl phosphate

The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the Enzyme Commission system.

Reversibility of this reaction is unspecified.

Imported from MetaCyc 13-Jan-2015 by Caspi R , SRI International

Enzymatic reaction of: undecaprenyl-pyrophosphate pyrophosphatase (Kdo2-lipid A phosphotransferase)

EC Number:

lipid A-core + di-trans,octa-cis-undecaprenyl diphosphate <=> lipid A-core 1-diphosphate + di-trans,octa-cis-undecaprenyl phosphate

The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the Enzyme Commission system.

Reversibility of this reaction is unspecified.

Sequence Features

Protein sequence of Kdo2-lipid A phosphotransferase with features indicated

Feature Class Location Common Name Citations Comment
Transmembrane-Region 6 -> 26 LpxT TM1
Transmembrane-Region 63 -> 83  
UniProt: Helical;; Non-Experimental Qualifier: potential;
Transmembrane-Region 63 -> 82 LpxT TM2
Transmembrane-Region 91 -> 111 LpxT TM3
Active-Site 116, 123, 124, 147, 148, 149, 150, 183, 184, 190, 194 acid phosphatase catalytic site
Transmembrane-Region 146 -> 166 LpxT TM4
Transmembrane-Region 168 -> 188  
UniProt: Helical;; Non-Experimental Qualifier: potential;
Transmembrane-Region 170 -> 189 LpxT TM5
Transmembrane-Region 195 -> 215 LpxT TM6

Gene Local Context (not to scale): ?

Gene local context diagram

Transcription Unit:

Transcription-unit diagram


Peter D. Karp on Thu Jan 16, 2003:
Predicted gene function revised as a result of E. coli genome reannotation by Serres et al. [Serres01 ].
Markus Krummenacker on Tue Oct 14, 1997:
Gene object created from Blattner lab Genbank (v. M52) entry.


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

Daley05: Daley DO, Rapp M, Granseth E, Melen K, Drew D, von Heijne G (2005). "Global topology analysis of the Escherichia coli inner membrane proteome." Science 308(5726);1321-3. PMID: 15919996

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

El05: El Ghachi M, Derbise A, Bouhss A, Mengin-Lecreulx D (2005). "Identification of multiple genes encoding membrane proteins with undecaprenyl pyrophosphate phosphatase (UppP) activity in Escherichia coli." J Biol Chem 280(19);18689-95. PMID: 15778224

Gerdes03: Gerdes SY, Scholle MD, Campbell JW, Balazsi G, Ravasz E, Daugherty MD, Somera AL, Kyrpides NC, Anderson I, Gelfand MS, Bhattacharya A, Kapatral V, D'Souza M, Baev MV, Grechkin Y, Mseeh F, Fonstein MY, Overbeek R, Barabasi AL, Oltvai ZN, Osterman AL (2003). "Experimental determination and system level analysis of essential genes in Escherichia coli MG1655." J Bacteriol 185(19);5673-84. PMID: 13129938

GOA01: GOA, DDB, FB, MGI, ZFIN (2001). "Gene Ontology annotation through association of InterPro records with GO terms."

Hayes06: Hayes ET, Wilks JC, Sanfilippo P, Yohannes E, Tate DP, Jones BD, Radmacher MD, BonDurant SS, Slonczewski JL (2006). "Oxygen limitation modulates pH regulation of catabolism and hydrogenases, multidrug transporters, and envelope composition in Escherichia coli K-12." BMC Microbiol 6;89. PMID: 17026754

Herrera10: Herrera CM, Hankins JV, Trent MS (2010). "Activation of PmrA inhibits LpxT-dependent phosphorylation of lipid A promoting resistance to antimicrobial peptides." Mol Microbiol 76(6);1444-60. PMID: 20384697

Joyce06: Joyce AR, Reed JL, White A, Edwards R, Osterman A, Baba T, Mori H, Lesely SA, Palsson BO, Agarwalla S (2006). "Experimental and computational assessment of conditionally essential genes in Escherichia coli." J Bacteriol 188(23);8259-71. PMID: 17012394

Lee07: Lee J, Jayaraman A, Wood TK (2007). "Indole is an inter-species biofilm signal mediated by SdiA." BMC Microbiol 7;42. PMID: 17511876

Pomposiello01: Pomposiello PJ, Bennik MH, Demple B (2001). "Genome-wide transcriptional profiling of the Escherichia coli responses to superoxide stress and sodium salicylate." J Bacteriol 183(13);3890-902. PMID: 11395452

Serres01: Serres MH, Gopal S, Nahum LA, Liang P, Gaasterland T, Riley M (2001). "A functional update of the Escherichia coli K-12 genome." Genome Biol 2(9);RESEARCH0035. PMID: 11574054

Tatar07: Tatar LD, Marolda CL, Polischuk AN, van Leeuwen D, Valvano MA (2007). "An Escherichia coli undecaprenyl-pyrophosphate phosphatase implicated in undecaprenyl phosphate recycling." Microbiology 153(Pt 8);2518-29. PMID: 17660416

Touze08: Touze T, Tran AX, Hankins JV, Mengin-Lecreulx D, Trent MS (2008). "Periplasmic phosphorylation of lipid A is linked to the synthesis of undecaprenyl phosphate." Mol Microbiol 67(2);264-77. PMID: 18047581

UniProt10: UniProt Consortium (2010). "UniProt version 2010-07 released on 2010-06-15 00:00:00." Database.

UniProtGOA11: UniProt-GOA (2011). "Gene Ontology annotation based on the manual assignment of UniProtKB Subcellular Location terms in UniProtKB/Swiss-Prot entries."

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

UniProtGOA12: UniProt-GOA (2012). "Gene Ontology annotation based on UniPathway vocabulary mapping."

Valvano08: Valvano MA (2008). "Undecaprenyl phosphate recycling comes out of age." Mol Microbiol 67(2);232-5. PMID: 18086187

Zhang07: Zhang N, Chen R, Young N, Wishart D, Winter P, Weiner JH, Li L (2007). "Comparison of SDS- and methanol-assisted protein solubilization and digestion methods for Escherichia coli membrane proteome analysis by 2-D LC-MS/MS." Proteomics 7(4);484-93. PMID: 17309111

Other References Related to Gene Regulation

Gogol11: Gogol EB, Rhodius VA, Papenfort K, Vogel J, Gross CA (2011). "Small RNAs endow a transcriptional activator with essential repressor functions for single-tier control of a global stress regulon." Proc Natl Acad Sci U S A 108(31);12875-80. PMID: 21768388

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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, biocyc13.