Octanoylation of early intermediates of mycobacterial methylglucose lipopolysaccharides.
Mycobacteria synthesize unique intracellular methylglucose lipopolysaccharides (MGLP) proposed to modulate fatty acid metabolism. In addition to the partial esterification of glucose or methylglucose units with short-chain fatty acids, octanoate was invariably detected on the MGLP reducing end. We have identified a novel sugar octanoyltransferase (OctT) that efficiently transfers octanoate to glucosylglycerate (GG) and diglucosylglycerate (DGG), the earliest intermediates in MGLP biosynthesis. Enzymatic studies, synthetic chemistry, NMR spectroscopy and mass spectrometry approaches suggest that, in contrast to the prevailing consensus, octanoate is not esterified to the primary hydroxyl group of glycerate but instead to the C6 OH of the second glucose in DGG. These observations raise important new questions about the MGLP reducing end architecture and about subsequent biosynthetic steps. Functional characterization of this unique octanoyltransferase, whose gene has been proposed to be essential for M. tuberculosis growth, adds new insights into a vital mycobacterial pathway, which may inspire new drug discovery strategies.
CNC - Center for Neuroscience and Cell Biology, University of Coimbra, 3004-517 Coimbra, Portugal.
Ana
A
Maranha
Department of Molecular and Cellular Biology, University of Guelph, Ontario, Canada.
Patrick J
PJ
Moynihan
ITQB - Instituto de Tecnologia Química Biológica, Universidade Nova de Lisboa, Portugal.
Vanessa
V
Miranda
ITQB - Instituto de Tecnologia Química Biológica, Universidade Nova de Lisboa, Portugal.
Eva
E
Correia Lourenço
CNC - Center for Neuroscience and Cell Biology, University of Coimbra, 3004-517 Coimbra, Portugal.
Daniela
D
Nunes-Costa
IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Portugal.|Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Portugal.
Joana S
JS
Fraga
IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Portugal.|Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Portugal.
Pedro
P
José Barbosa Pereira
IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Portugal.|Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Portugal.
Sandra
S
Macedo-Ribeiro
ITQB - Instituto de Tecnologia Química Biológica, Universidade Nova de Lisboa, Portugal.
M Rita
MR
Ventura
Department of Molecular and Cellular Biology, University of Guelph, Ontario, Canada.
Anthony J
AJ
Clarke
CNC - Center for Neuroscience and Cell Biology, University of Coimbra, 3004-517 Coimbra, Portugal.|III/UC- Instituto de Investigação Interdisciplinar, University of Coimbra, Portugal.
Nuno
N
Empadinhas
D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D005227:Fatty Acids / Q000378:metabolism; D006031:Glycosylation; D016695:Glycosyltransferases / Q000235:genetics / Q000378:metabolism; D007700:Kinetics; D008070:Lipopolysaccharides / Q000096:biosynthesis*; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D009161:Mycobacterium / Q000201:enzymology / Q000378:metabolism*; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000302:isolation & purification; D013379:Substrate Specificity
D001426:Bacterial Proteins; D005227:Fatty Acids; D008070:Lipopolysaccharides; D011994:Recombinant Proteins; D016695:Glycosyltransferases