title: SMb20651 is another acyl carrier protein from Sinorhizobium meliloti.
abstract: Acyl carrier proteins (ACPs) are small acidic proteins that carry growing acyl chains during fatty acid or polyketide synthesis. In rhizobia, there are four different and well-characterized ACPs: AcpP, NodF, AcpXL and RkpF. The genome sequence of Sinorhizobium meliloti 1021 reveals two additional ORFs that possibly encode additional ACPs. One of these, smb20651, is located on the plasmid pSymB as part of an operon. The genes of the operon encode a putative asparagine synthetase (AsnB), the predicted ACP (SMb20651), a putative long-chain fatty acyl-CoA ligase (SMb20650) and a putative ammonium-dependent NAD+ synthetase (NadE1). When SMb20651 was overexpressed in Escherichia coli, [3H]beta-alanine, a biosynthetic building block of 4'-phosphopantetheine, was incorporated into the protein in vivo. The purified SMb20651 was modified with 4'-phosphopantetheine in the presence of S. meliloti holo-ACP synthase (AcpS). Also, holo-SMb20651 was modified in vitro with a malonyl group by malonyl CoA-ACP transacylase. In E. coli, coexpression of SMb20651 together with other proteins such as AcpS and SMb20650 led to the formation of additional forms of SMb20651. In this bacterium, acylation of SMb20651 with C12 : 0 or C18 : 0 fatty acids was detected, demonstrating that this protein is involved in fatty acid biosynthesis or transfer. Expression of SMb20651 was detected in S. meliloti as holo-SMb20651 and acyl-SMb20651.
authors.affiliation: Programa de Ecología Genómica, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Apdo. Postal 565-A, Cuernavaca, Morelos C. P. 62251, Mexico.
authors.forename: Ana Laura
authors.initials: AL
authors.lastname: Ramos-Vega
authors.affiliation: Programa de Ecología Genómica, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Apdo. Postal 565-A, Cuernavaca, Morelos C. P. 62251, Mexico.
authors.forename: Yadira
authors.initials: Y
authors.lastname: Dávila-Martínez
authors.affiliation: Programa de Ecología Genómica, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Apdo. Postal 565-A, Cuernavaca, Morelos C. P. 62251, Mexico.
authors.forename: Christian
authors.initials: C
authors.lastname: Sohlenkamp
authors.affiliation: Programa de Genómica Funcional de Procariontes, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Apdo. Postal 565-A, Cuernavaca, Morelos C. P. 62251, Mexico.
authors.forename: Sandra
authors.initials: S
authors.lastname: Contreras-Martínez
authors.affiliation: Programa de Genómica Funcional de Procariontes, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Apdo. Postal 565-A, Cuernavaca, Morelos C. P. 62251, Mexico.
authors.forename: Sergio
authors.initials: S
authors.lastname: Encarnación
authors.affiliation: Programa de Ecología Genómica, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Apdo. Postal 565-A, Cuernavaca, Morelos C. P. 62251, Mexico.
authors.forename: Otto
authors.initials: O
authors.lastname: Geiger
authors.affiliation: Programa de Ecología Genómica, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Apdo. Postal 565-A, Cuernavaca, Morelos C. P. 62251, Mexico.
authors.forename: Isabel M
authors.initials: IM
authors.lastname: López-Lara
mesh_terms: D000213:Acyl Carrier Protein / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D051080:Acyl-Carrier Protein S-Malonyltransferase / Q000378:metabolism; D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D008025:Ligases / Q000378:metabolism; D000455:Medicago sativa / Q000382:microbiology; D016297:Mutagenesis, Site-Directed; D009876:Operon; D010204:Pantetheine / Q000031:analogs & derivatives / Q000378:metabolism; D011817:Rabbits; D016962:Sinorhizobium meliloti / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*
chemical_list: D000213:Acyl Carrier Protein; D000907:Antibodies, Bacterial; D001426:Bacterial Proteins; D010204:Pantetheine; D051080:Acyl-Carrier Protein S-Malonyltransferase; D008025:Ligases; C003129:4'-phosphopantetheine