title: The versatile TolC-like Slr1270 in the cyanobacterium Synechocystis sp. PCC 6803.
abstract: Here we report on the functional characterization of the hypothetical protein Slr1270, a TolC homologue in Synechocystis sp. PCC 6803. Analysis of a slr1270 insertion deletion mutant and respective wild-type revealed that the mutant presents increased susceptibility to antibiotics. In addition, a detailed study of the exoproteome showed that Slr1270 mediates protein secretion. Among the protein substrates dependent on Slr1270 function, we found the S-layer structural component. Electron microscopy studies of the slr1270 mutant showed that the S-layer is indeed absent. The requirement of functional Slr1270 for protein secretion and drug resistance mechanisms suggests that Slr1270 plays a role similar to that described for TolC in other bacteria. Additional phenotypic traits could also be observed, including slower growth rates at low temperature, impairment in biofilm formation and increased activity of enzymes detoxifying reactive oxygen species. Furthermore, an increased capacity of outer membrane vesicles (OMVs) formation and release was also found in the slr1270 mutant, a feature that has not yet been observed in bacteria lacking TolC. This work highlights the marked physiological fitness that the TolC-like Slr1270 bestows to the photosynthetic model Synechocystis sp. PCC 6803 and presents a valuable model for studying OMVs formation and release.
authors.affiliation: i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.|IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal.
authors.forename: Paulo
authors.initials: P
authors.lastname: Oliveira
authors.affiliation: i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.|IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal.|Faculdade de Ciências, Departamento de Biologia, Universidade do Porto, Porto, Portugal.
authors.forename: Nuno M
authors.initials: NM
authors.lastname: Martins
authors.affiliation: i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.|IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal.
authors.forename: Marina
authors.initials: M
authors.lastname: Santos
authors.affiliation: i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.|IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal.
authors.forename: Filipe
authors.initials: F
authors.lastname: Pinto
authors.affiliation: i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.|IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal.
authors.forename: Zsófia
authors.initials: Z
authors.lastname: Büttel
authors.affiliation: ChELSI Institute, Chemical and Biological Engineering, University of Sheffield, Sheffield, UK.
authors.forename: Narciso A S
authors.initials: NA
authors.lastname: Couto
authors.affiliation: ChELSI Institute, Chemical and Biological Engineering, University of Sheffield, Sheffield, UK.
authors.forename: Phillip C
authors.initials: PC
authors.lastname: Wright
authors.affiliation: i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.|IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal.|Faculdade de Ciências, Departamento de Biologia, Universidade do Porto, Porto, Portugal.
authors.forename: Paula
authors.initials: P
authors.lastname: Tamagnini
mesh_terms: D000900:Anti-Bacterial Agents / Q000378:metabolism / Q000494:pharmacology*; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics / Q000502:physiology*; D001692:Biological Transport / Q000235:genetics; D002374:Catalase / Q000235:genetics / Q000378:metabolism; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D054643:INDEL Mutation / Q000235:genetics; D026901:Membrane Transport Proteins / Q000235:genetics*; D009195:Peroxidase / Q000235:genetics / Q000378:metabolism; D010788:Photosynthesis; D017382:Reactive Oxygen Species / Q000378:metabolism; D013482:Superoxide Dismutase / Q000235:genetics / Q000378:metabolism; D046939:Synechocystis / Q000187:drug effects* / Q000235:genetics* / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D001425:Bacterial Outer Membrane Proteins; D026901:Membrane Transport Proteins; D017382:Reactive Oxygen Species; D002374:Catalase; D009195:Peroxidase; D013482:Superoxide Dismutase