Functional and small-angle X-ray scattering studies of a new stationary phase survival protein E (SurE) from Xylella fastidiosa--evidence of allosteric behaviour.
The genome data of bacterium Xylella fastidiosa strain 9a5c has identified several orfs related to its phytopathogenic adaptation and survival. Among these genes, the surE codifies a survival protein E (XfSurE) whose function is not so well understood, but functional assays in Escherichia coli revealed nucleotidase and exopolyphosphate activity. In the present study, we report the XfSurE protein overexpression in E. coli and its purification. The overall secondary structure was analyzed by CD. Small-angle X-ray scattering and gel filtration techniques demonstrated that the oligomeric state of the protein in solution is a tetramer. In addition, functional kinetics experiments were carried out with several monophosphate nucleoside substrates and revealed a highly positive cooperativity. An allosteric mechanism involving torsion movements in solution is proposed to explain the cooperative behaviour of XfSurE. This is the first characterization of a SurE enzyme from a phytopathogen organism and, to our knowledge, the first solution structure of a SurE protein to be described.
Saraiva
Antonio M
AM
Centro de Biologia Molecular e Engenharia Genética (CBMEG), Universidade Estadual de Campinas, Campinas São Paulo, Brazil.
Reis
Marcelo A
MA
Tada
Susely F
SF
Rosselli-Murai
Luciana K
LK
Schneider
Dilaine R S
DR
Pelloso
Alexandre C
AC
Toledo
Marcelo A S
MA
Giles
Carlos
C
Aparicio
Ricardo
R
de Souza
Anete P
AP
D000494:Allosteric Regulation; D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism*; D002850:Chromatography, Gel; D002942:Circular Dichroism; D055503:Protein Multimerization; D017433:Protein Structure, Secondary; D053838:Scattering, Small Angle; D014965:X-Rays; D044167:Xylella / Q000378:metabolism*
D001426:Bacterial Proteins