title: Fatty acid synthesis in Xylella fastidiosa: correlations between genome studies, 13C NMR data, and molecular models.
abstract: Xylella fastidiosa was the first plant pathogen to have its complete genome sequence elucidated. Routine database analyses suggested that two enzymes essential for fatty acid synthesis were missing, one of these is the holo-acyl-carrier-protein synthase. However, here we demonstrate, using (13)C NMR spectroscopy, that X. fastidiosa is indeed able to synthesize fatty acids from acetate via an apparently conventional metabolic pathway. We further identify a gene product HetI, an alternative phosphopantetheinyl transferase, which we propose to fill the missing link. Homology modeling of HetI shows conservation of the Coenzyme A binding site suggesting it to be an active enzyme and reveals several interesting structural features when compared with the surfactin synthase-activating enzyme, on which the model was built. These include a simplified topology due to N- and C-terminal deletions and the observation of a novel serine ladder.
authors.affiliation: Embrapa Instrumentação Agropecuária, Rua XV de Novembro 1452, CEP 13560-970 São Carlos, São Paulo, Brazil.
authors.forename: Denise
authors.initials: D
authors.lastname: Osiro
authors.forename: João Renato C
authors.initials: JR
authors.lastname: Muniz
authors.forename: Helvécio Della
authors.initials: HD
authors.lastname: Coleta Filho
authors.forename: Alessandra Alves
authors.initials: AA
authors.lastname: de Sousa
authors.forename: Marcos Antonio
authors.initials: MA
authors.lastname: Machado
authors.forename: Richard C
authors.initials: RC
authors.lastname: Garratt
authors.forename: Luiz Alberto
authors.initials: LA
authors.lastname: Colnago
mesh_terms: D000085:Acetates / Q000378:metabolism; D000595:Amino Acid Sequence; D002247:Carbon Isotopes; D003198:Computer Simulation; D005227:Fatty Acids / Q000096:biosynthesis*; D020869:Gene Expression Profiling / Q000379:methods*; D016680:Genome, Bacterial; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011487:Protein Conformation; D020539:Sequence Analysis, Protein; D017386:Sequence Homology, Amino Acid; D013223:Statistics as Topic; D017855:Transferases (Other Substituted Phosphate Groups) / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D044167:Xylella / Q000378:metabolism*
chemical_list: D000085:Acetates; D002247:Carbon Isotopes; D005227:Fatty Acids; D017855:Transferases (Other Substituted Phosphate Groups); C021364:holo-(acyl-carrier-protein) synthase