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The Anabaena sp. PCC 7120 Exoproteome: Taking a Peek outside the Box.

Oliveira P, Martins NM, Santos M, Couto NA, Wright PC, Tamagnini P - Life (Basel) (2015)

Bottom Line: The evidence presented here shows that Anabaena sp.Furthermore, the activity of selected exoproteins associated with oxidative stress has been assessed, suggesting their involvement in redox homeostasis mechanisms in the extracellular space.Finally, we discuss our results in light of other cyanobacterial exoproteome studies and focus on the potential of exploring cyanobacteria as cell factories to produce and secrete selected proteins.

View Article: PubMed Central - PubMed

Affiliation: Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto 4150-180, Portugal. paulo.oliveira@ibmc.up.pt.

ABSTRACT
The interest in examining the subset of proteins present in the extracellular milieu, the exoproteome, has been growing due to novel insights highlighting their role on extracellular matrix organization and biofilm formation, but also on homeostasis and development. The cyanobacterial exoproteome is poorly studied, and the role of cyanobacterial exoproteins on cell wall biogenesis, morphology and even physiology is largely unknown. Here, we present a comprehensive examination of the Anabaena sp. PCC 7120 exoproteome under various growth conditions. Altogether, 139 proteins belonging to 16 different functional categories have been identified. A large fraction (48%) of the identified proteins is classified as "hypothetical", falls into the "other categories" set or presents no similarity to other proteins. The evidence presented here shows that Anabaena sp. PCC 7120 is capable of outer membrane vesicle formation and that these vesicles are likely to contribute to the exoproteome profile. Furthermore, the activity of selected exoproteins associated with oxidative stress has been assessed, suggesting their involvement in redox homeostasis mechanisms in the extracellular space. Finally, we discuss our results in light of other cyanobacterial exoproteome studies and focus on the potential of exploring cyanobacteria as cell factories to produce and secrete selected proteins.

No MeSH data available.


Related in: MedlinePlus

Exoproteome profiles of Anabaena sp. PCC 7120 cultivated under various growth conditions. Wild-type cells of Anabaena sp. PCC 7120 were grown in nitrogen-fixing conditions (N2) or in medium supplemented with nitrate (NO3−) or ammonia (NH4+). The protein content present in 5 mL of each cell-free growth medium was separated by SDS-polyacrylamide gel electrophoresis and the exoproteomes visualized by Coomassie Blue staining. Bands and gel areas selected for in-gel trypsin digestion and further protein identification by mass spectrometry are highlighted on the right of each panel by arrowheads and lines, respectively. Proteins identified in each band and the gel portion are listed in the Supplementary Information. The molecular masses of the Precision Plus Protein All Blue standard (Bio-Rad, Hercules, CA, USA) are indicated on the left.
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life-05-00130-f001: Exoproteome profiles of Anabaena sp. PCC 7120 cultivated under various growth conditions. Wild-type cells of Anabaena sp. PCC 7120 were grown in nitrogen-fixing conditions (N2) or in medium supplemented with nitrate (NO3−) or ammonia (NH4+). The protein content present in 5 mL of each cell-free growth medium was separated by SDS-polyacrylamide gel electrophoresis and the exoproteomes visualized by Coomassie Blue staining. Bands and gel areas selected for in-gel trypsin digestion and further protein identification by mass spectrometry are highlighted on the right of each panel by arrowheads and lines, respectively. Proteins identified in each band and the gel portion are listed in the Supplementary Information. The molecular masses of the Precision Plus Protein All Blue standard (Bio-Rad, Hercules, CA, USA) are indicated on the left.

Mentions: Currently, in our group, we are identifying the exoproteome of various cyanobacterial strains, aiming at understanding the role of exoproteins on the cell structure and physiology. Briefly, the cells were grown under different conditions; samples were taken periodically during the culture growth and the growth medium was separated from the cells by mild centrifugation and filtration. The resulting cell-free medium was then concentrated by ultrafiltration (for details, see the Experimental Section). The exoproteome of Anabaena sp. PCC 7120 grown in medium with different combined nitrogen sources (nitrate or ammonia) or in nitrogen-fixing conditions separated by SDS-polyacrylamide gel electrophoresis is presented in Figure 1. The total amount of proteins accumulating in the growth medium, regardless of the cultivating conditions, is substantial, supporting the notion that Anabaena sp. PCC 7120 can indeed export and release proteins to the extracellular space with a specific function in that particular environment. This hypothesis gets further support from the observation that the exoproteome profiles in the three conditions tested present differential compositions, indicating that some proteins are specifically expressed in a given condition and could be exported to the extracellular milieu to fulfil a particular task.


The Anabaena sp. PCC 7120 Exoproteome: Taking a Peek outside the Box.

Oliveira P, Martins NM, Santos M, Couto NA, Wright PC, Tamagnini P - Life (Basel) (2015)

Exoproteome profiles of Anabaena sp. PCC 7120 cultivated under various growth conditions. Wild-type cells of Anabaena sp. PCC 7120 were grown in nitrogen-fixing conditions (N2) or in medium supplemented with nitrate (NO3−) or ammonia (NH4+). The protein content present in 5 mL of each cell-free growth medium was separated by SDS-polyacrylamide gel electrophoresis and the exoproteomes visualized by Coomassie Blue staining. Bands and gel areas selected for in-gel trypsin digestion and further protein identification by mass spectrometry are highlighted on the right of each panel by arrowheads and lines, respectively. Proteins identified in each band and the gel portion are listed in the Supplementary Information. The molecular masses of the Precision Plus Protein All Blue standard (Bio-Rad, Hercules, CA, USA) are indicated on the left.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4390845&req=5

life-05-00130-f001: Exoproteome profiles of Anabaena sp. PCC 7120 cultivated under various growth conditions. Wild-type cells of Anabaena sp. PCC 7120 were grown in nitrogen-fixing conditions (N2) or in medium supplemented with nitrate (NO3−) or ammonia (NH4+). The protein content present in 5 mL of each cell-free growth medium was separated by SDS-polyacrylamide gel electrophoresis and the exoproteomes visualized by Coomassie Blue staining. Bands and gel areas selected for in-gel trypsin digestion and further protein identification by mass spectrometry are highlighted on the right of each panel by arrowheads and lines, respectively. Proteins identified in each band and the gel portion are listed in the Supplementary Information. The molecular masses of the Precision Plus Protein All Blue standard (Bio-Rad, Hercules, CA, USA) are indicated on the left.
Mentions: Currently, in our group, we are identifying the exoproteome of various cyanobacterial strains, aiming at understanding the role of exoproteins on the cell structure and physiology. Briefly, the cells were grown under different conditions; samples were taken periodically during the culture growth and the growth medium was separated from the cells by mild centrifugation and filtration. The resulting cell-free medium was then concentrated by ultrafiltration (for details, see the Experimental Section). The exoproteome of Anabaena sp. PCC 7120 grown in medium with different combined nitrogen sources (nitrate or ammonia) or in nitrogen-fixing conditions separated by SDS-polyacrylamide gel electrophoresis is presented in Figure 1. The total amount of proteins accumulating in the growth medium, regardless of the cultivating conditions, is substantial, supporting the notion that Anabaena sp. PCC 7120 can indeed export and release proteins to the extracellular space with a specific function in that particular environment. This hypothesis gets further support from the observation that the exoproteome profiles in the three conditions tested present differential compositions, indicating that some proteins are specifically expressed in a given condition and could be exported to the extracellular milieu to fulfil a particular task.

Bottom Line: The evidence presented here shows that Anabaena sp.Furthermore, the activity of selected exoproteins associated with oxidative stress has been assessed, suggesting their involvement in redox homeostasis mechanisms in the extracellular space.Finally, we discuss our results in light of other cyanobacterial exoproteome studies and focus on the potential of exploring cyanobacteria as cell factories to produce and secrete selected proteins.

View Article: PubMed Central - PubMed

Affiliation: Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto 4150-180, Portugal. paulo.oliveira@ibmc.up.pt.

ABSTRACT
The interest in examining the subset of proteins present in the extracellular milieu, the exoproteome, has been growing due to novel insights highlighting their role on extracellular matrix organization and biofilm formation, but also on homeostasis and development. The cyanobacterial exoproteome is poorly studied, and the role of cyanobacterial exoproteins on cell wall biogenesis, morphology and even physiology is largely unknown. Here, we present a comprehensive examination of the Anabaena sp. PCC 7120 exoproteome under various growth conditions. Altogether, 139 proteins belonging to 16 different functional categories have been identified. A large fraction (48%) of the identified proteins is classified as "hypothetical", falls into the "other categories" set or presents no similarity to other proteins. The evidence presented here shows that Anabaena sp. PCC 7120 is capable of outer membrane vesicle formation and that these vesicles are likely to contribute to the exoproteome profile. Furthermore, the activity of selected exoproteins associated with oxidative stress has been assessed, suggesting their involvement in redox homeostasis mechanisms in the extracellular space. Finally, we discuss our results in light of other cyanobacterial exoproteome studies and focus on the potential of exploring cyanobacteria as cell factories to produce and secrete selected proteins.

No MeSH data available.


Related in: MedlinePlus