201. SMc01553 is the sixth acyl carrier protein in Sinorhizobium meliloti 1021
- Author
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Sandra Contreras-Martínez, Yadira Dávila-Martínez, Otto Geiger, Isabel M. López-Lara, Ana Laura Ramos-Vega, and Sergio Encarnación
- Subjects
Mutant ,Biology ,medicine.disease_cause ,Microbiology ,Protein Structure, Secondary ,chemistry.chemical_compound ,Plasmid ,Protein structure ,Bacterial Proteins ,medicine ,Acyl Carrier Protein ,Escherichia coli ,Sinorhizobium meliloti ,Reverse Transcriptase Polymerase Chain Reaction ,biology.organism_classification ,Recombinant Proteins ,Open reading frame ,Acyl carrier protein ,RNA, Bacterial ,chemistry ,Biochemistry ,Pantetheine ,biology.protein ,bacteria ,lipids (amino acids, peptides, and proteins) ,Phosphopantetheine - Abstract
Acyl carrier proteins (ACPs) are required for the transfer of acyl intermediates during fatty acid and polyketide syntheses. InSinorhizobium meliloti1021 there are five known ACPs: AcpP, NodF, AcpXL, the ACP domain in RkpA and SMb20651. The genome sequence ofS. meliloti1021 also reveals the ORF SMc01553, annotated as a putative ACP.smc01553is part of a 6.6 kb DNA region that is duplicated in the chromosome and in the pSymb plasmid, the result of a recent duplication event. SMc01553 overexpressed inEscherichia coliwas labelledin vivowith [3H]β-alanine, a biosynthetic building block of the 4′-phosphopantetheine prosthetic group of ACPs. The purified SMc01553 was modified with 4′-phosphopantetheine in the presence ofS. melilotiholo-ACP synthase, and this modification resulted in a major conformational change of the protein structure, since the holo-form runs faster in native PAGE than the apo-form. SMc01553 could not be loaded with a malonyl group by malonyl-CoA-ACP transacylase fromS. meliloti. Using RT-PCR we could show the presence of mRNA for SMc01553 and of the duplicated ORF SMb22007 in cultures ofS. meliloti. However, a mutant in which the two duplicated regions were deleted did not show any different phenotype with respect to the wild-type in the free-living or symbiotic lifestyle.
- Published
- 2009