Taxonomic group: bacteria / Proteobacteria
(Phylum: Proteobacteria)
Associated disease: infection due to Escherichia coli [ICD11:
XN6P4 
]
NCBI PubMed ID: 24046865Publication DOI: 10.1016/j.bbalip.2013.04.002Journal NLM ID: 0217513Publisher: Elsevier
Correspondence: chsohlen
ccg.unam.mx; B.O. Ingram <boingram
email.unc.edu>
Institutions: Department of Biochemistry, Duke University Medical Center, Durham, NC 27710, USA, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Av. Universidad s/n, Apdo. Postal 565-A, Cuernavaca, Morelos, CP62210, Mexico
The lipid A component of lipopolysaccharide from the nitrogen-fixing plant endosymbiont, Rhizobium etli, is structurally very different from that found in most enteric bacteria. The lipid A from free-living R. etli is structurally heterogeneous and exists as a mixture of species which are either pentaacylated or tetraacylated. In contrast, the lipid A from R. etli bacteroids is reported to consist exclusively of tetraacylated lipid A species. The tetraacylated lipid A species in both cases lack a β-hydroxymyristoyl chain at the 3-position of lipid A. Here, we show that the lipid A modification enzyme responsible for 3-O deacylation in R. etli is a homolog of the PagL protein originally described in Salmonella enterica sv. typhimurium. In contrast to the PagL proteins described from other species, R. etli PagL displays a calcium dependency. To determine the importance of the lipid A modification catalyzed by PagL, we isolated and characterized a R. etli mutant deficient in the pagL gene. Mass spectrometric analysis confirmed that the mutant strain was exclusively tetraacylated and radiochemical analysis revealed that 3-O deacylase activity was absent in membranes prepared from the mutant. The R. etli mutant was not impaired in its ability to form nitrogen-fixing nodules on Phaseolus vulgaris but it displayed slower nodulation kinetics relative to the wild-type strain. The lipid A modification catalyzed by R. etli PagL, therefore, is not required for nodulation but may play other roles such as protecting bacterial endosymbionts from plant immune responses during infection.
Lipopolysaccharide, lipid A, Rhizobium etli, Gram-negative bacteria, pagL
Structure type: oligomer
Location inside paper: p.1251, fig.1A
Compound class: LPS, lipid A, glycolipid, phosphoglycolipid
Contained glycoepitopes: IEDB_135394,IEDB_135515,IEDB_141807,IEDB_151531,IEDB_176772,IEDB_534864
Methods: DNA techniques, TLC, ESI-MS, biological assays, genetic methods, biochemical methods, LC-MS, assay of polymyxin sensitivity, radiochemical analysis
Biosynthesis and genetic data: genetic data
Related record ID(s): 32039, 32040, 32041, 32042
NCBI Taxonomy refs (TaxIDs): 562
Show glycosyltransferases
There is only one chemically distinct structure:
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