Structural analysis of Herbaspirillum seropedicae lipid-A and of two mutants defective to colonize maize roots.
Lipid-A was isolated by mild acid hydrolysis from lipopolysaccharides extracted from cells of Herbaspirillum seropedicae, strain SMR1, and from two mutants deficient in the biosynthesis of rhamnose (rmlB⁻ and rmlC⁻). Structural analyzes were carried out using MALDI-TOF and derivatization by per-O-trimethylsilylation followed by GC-MS in order to determine monosaccharide and fatty acid composition. De-O-acylation was also performed to determine the presence of N-linked fatty acids. Lipid-A from H. seropedicae SMR1 showed a major structure comprising 2-amino-2-deoxy-glucopyranose-(1→6)-2-amino-2-deoxy-glucopyranose phosphorylated at C4' and C1 positions, each carrying a unit of 4-amino-4-deoxy-arabinose. C2 and C2' positions were substituted by amide-linked 3-hydroxy-dodecanoic acids. Both rhamnose-defective mutants showed similar structure for their lipid-A moieties, except for the lack of 4-amino-4-deoxy-arabinose units attached to phosphoryl groups.
Setor Litoral, Universidade Federal do Paraná, Matinhos, PR, Brazil. rvserrato@ufpr.br
Rodrigo V
RV
Serrato
Eduardo
E
Balsanelli
Guilherme L
GL
Sassaki
Russell W
RW
Carlson
Artur
A
Muszynski
Rose A
RA
Monteiro
Fábio O
FO
Pedrosa
Emanuel M
EM
Souza
Marcello
M
Iacomini
D042803:Herbaspirillum / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism / Q000502:physiology*; D008050:Lipid A / Q000737:chemistry* / Q000302:isolation & purification; D016296:Mutagenesis; D009154:Mutation; D018517:Plant Roots / Q000382:microbiology*; D012210:Rhamnose / Q000096:biosynthesis; D003313:Zea mays / Q000382:microbiology*
D008050:Lipid A; D012210:Rhamnose