title: iTRAQ-based quantitative proteomic analysis of Gloeothece sp. PCC 6909: Comparison with its sheathless mutant and adaptations to nitrate deficiency and sulfur limitation.
abstract: Gloeothece sp. PCC 6909 is a unicellular N(2)-fixing cyanobacterium with a well defined and highly developed sheath surrounding its cells. A sheathless mutant of this strain was previously obtained by chemical mutagenesis and, although lacking the sheath, it releases large amounts of polysaccharides into the culture medium. To provide a global understanding on the metabolic differences between the two phenotypes, the proteomes of the wild type and mutant were analyzed using a cross-species proteomics approach coupled with iTRAQ isobaric tagging technology, since their genome sequences are not yet available. Effects arising from the presence/absence of nitrate and sulfur are presented as two metabolically directed follow-up iTRAQ studies. These nutrients are believed to play a major role in Gloeothece's metabolism, including the production of extracellular polymeric substances - EPS. 454, 124, and 53 proteins were identified and reliably quantified using homology anchoring approaches for iTRAQ previously described. The results obtained strongly suggest that the chemical mutagenesis affected the regulation of a number of key cellular processes, as revealed by the significant fold changes observed for proteins covering a large spectrum of functional groups. Moreover, they provide new insights on the adaptations of Gloeothece cells to nitrate-deficiency and sulfur-limitation.
authors.affiliation: IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Rua do Campo Alegre 823, 4150-180 Porto, Portugal.
authors.forename: Sara B
authors.initials: SB
authors.lastname: Pereira
authors.forename: Saw Yen
authors.initials: SY
authors.lastname: Ow
authors.forename: Martin E
authors.initials: ME
authors.lastname: Barrios-Llerena
authors.forename: Phillip C
authors.initials: PC
authors.lastname: Wright
authors.forename: Pedro
authors.initials: P
authors.lastname: Moradas-Ferreira
authors.forename: Paula
authors.initials: P
authors.lastname: Tamagnini
mesh_terms: D001426:Bacterial Proteins / Q000032:analysis* / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D000458:Cyanobacteria / Q000145:classification / Q000254:growth & development / Q000378:metabolism*; D009154:Mutation; D009566:Nitrates / Q000378:metabolism*; D009584:Nitrogen / Q000378:metabolism; D040901:Proteomics / Q000379:methods*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods; D013194:Staining and Labeling; D013455:Sulfur / Q000378:metabolism*; D053719:Tandem Mass Spectrometry / Q000379:methods
chemical_list: D001426:Bacterial Proteins; D009566:Nitrates; D013455:Sulfur; D009584:Nitrogen