Taxonomic group: bacteria / Proteobacteria
(Phylum: Proteobacteria)
Associated disease: infection due to Escherichia coli [ICD11:
XN6P4 
]
The structure was elucidated in this paperNCBI PubMed ID: 22158874Publication DOI: 10.1074/jbc.M111.308486Journal NLM ID: 2985121RPublisher: Baltimore, MD: American Society for Biochemistry and Molecular Biology
Correspondence: pwang11
gsu.edu
Institutions: Department of Chemistry, Georgia State University, Atlanta, Georgia 30302, USA
The WaaL-mediated ligation of O-antigen onto the core region of the lipid A-core block is an important step in the lipopolysaccharide (LPS) biosynthetic pathway. Although the LPS biosynthesis has been largely characterized, only a limited amount of in vitro biochemical evidence has been established for the ligation reaction. Such limitations have primarily resulted from the barriers in purifying WaaL homologues and obtaining chemically defined substrates. Accordingly, we describe herein a chemical biology approach that enabled the reconstitution of this ligation reaction. The O-antigen repeating unit (O-unit) of Escherichia coli O86 was first enzymatically assembled via sequential enzymatic glycosylation of a chemically synthesized GalNAc-pyrophosphate-undecaprenyl precursor. Subsequent expression of WaaL through use of a chaperone co-expression system then enabled the demonstration of the in vitro ligation between the synthesized donor (O-unit-pyrophosphate-undecaprenyl) and the isolated lipid A-core acceptor. The previously reported ATP and divalent metal cation dependence were not observed using this system. Further analyses of other donor substrates revealed that WaaL possesses a highly relaxed specificity toward both the lipid moiety and the glycan moiety of the donor. Lastly, three conserved amino acid residues identified by sequence alignment were found essential for the WaaL activity. Taken together, the present work represents an in vitro systematic investigation of the WaaL function using a chemical biology approach, providing a system that could facilitate the elucidation of the mechanism of WaaL-catalyzed ligation reaction
Lipopolysaccharide, biosynthesis, antigen, LPS, core, biosynthetic, chemistry, expression, genetics, metabolism, O-antigen, repeating unit, O antigen, Research, Escherichia, Escherichia coli, acid, conserved, lipid, antigens, protein, O antigens, O-antigens, glycan, specificity, activity, chemical, core region, region, biochemical, precursor, enzymatic, mechanism, elucidation, sequence, Substrate Specificity, defined, function, mutation, biology, amino, acceptor, glycosylation, pathway, lipopolysaccharide O-antigen, Cell Membrane, proteins, reaction, substrate, amino acid, enzymatic glycosylation, Ligation, enzymology, in vitro, use, Sequence Alignment, ATP, isolation & purification, sequential, E. coli, approach, systematic, cytology, cation, dependence, Escherichia coli Proteins, barrier, metal, Carbon-Oxygen Ligases, coexpression, Diphosphates, Ligases, metal cation, membrane enzyme
Structure type: monomer
Location inside paper: p.5359, fig.2
Aglycon: geranyl, undecyl, cis-farnesyl, pentaprenyl, heptaprenyl, solanesyl, undecaprenyl
Trivial name: GalNAc-pyrophosphate-undecaprenyl precursor
Contained glycoepitopes: IEDB_130648,IEDB_137473,IEDB_1391961,IEDB_141584,IEDB_885822
Methods: SDS-PAGE, ESI-MS, Western blotting, genetic methods, biochemical methods, chemoenzymatic synthesis
Synthetic data: chemical
Related record ID(s): 30185
NCBI Taxonomy refs (TaxIDs): 2162909
Show glycosyltransferases
There is only one chemically distinct structure:
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