Functional and structural studies of the disulfide isomerase DsbC from the plant pathogen Xylella fastidiosa reveals a redox-dependent oligomeric modulation in vitro.
Xylella fastidiosa is a Gram-negative bacterium that grows as a biofilm inside the xylem vessels of susceptible plants and causes several economically relevant crop diseases. In the present study, we report the functional and low-resolution structural characterization of the X. fastidiosa disulfide isomerase DsbC (XfDsbC). DsbC is part of the disulfide bond reduction/isomerization pathway in the bacterial periplasm and plays an important role in oxidative protein folding. In the present study, we demonstrate the presence of XfDsbC during different stages of X. fastidiosa biofilm development. XfDsbC was not detected during X. fastidiosa planktonic growth; however, after administering a sublethal copper shock, we observed an overexpression of XfDsbC that also occurred during planktonic growth. These results suggest that X. fastidiosa can use XfDsbC in vivo under oxidative stress conditions similar to those induced by copper. In addition, using dynamic light scattering and small-angle X-ray scattering, we observed that the oligomeric state of XfDsbC in vitro may be dependent on the redox environment. Under reducing conditions, XfDsbC is present as a dimer, whereas a putative tetrameric form was observed under nonreducing conditions. Taken together, our findings demonstrate the overexpression of XfDsbC during biofilm formation and provide the first structural model of a bacterial disulfide isomerase in solution.
Centro de Biologia Molecular e Engenharia Genética (CBMEG), Universidade Estadual de Campinas, Campinas, São Paulo, Brazil.
Clelton A
CA
Santos
Marcelo A S
MA
Toledo
Daniela B B
DB
Trivella
Lilian L
LL
Beloti
Dilaine R S
DR
Schneider
Antonio M
AM
Saraiva
Aline
A
Crucello
Adriano R
AR
Azzoni
Alessandra A
AA
Souza
Ricardo
R
Aparicio
Anete P
AP
Souza
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D018441:Biofilms / Q000187:drug effects / Q000254:growth & development; D003300:Copper / Q000494:pharmacology; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics / Q000254:growth & development; D005816:Genetic Complementation Test; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009154:Mutation; D010084:Oxidation-Reduction; D010935:Plant Diseases / Q000382:microbiology; D019704:Protein Disulfide-Isomerases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D055503:Protein Multimerization; D020836:Protein Structure, Quaternary; D053838:Scattering, Small Angle; D017386:Sequence Homology, Amino Acid; D014961:X-Ray Diffraction; D044167:Xylella / Q000201:enzymology* / Q000235:genetics / Q000502:physiology
D001426:Bacterial Proteins; D003300:Copper; D019704:Protein Disulfide-Isomerases