Analysis of heat-induced changes in protein expression of Stenotrophomonas maltophilia K279a reveals a role for GroEL in the host-temperature adaptation.
Stenotrophomonas maltophilia is a microorganism of environmental and clinical importance as well as a frequent airway colonizer of cystic fibrosis (CF) individuals. We combined 2-DE and MALDI-TOF MS to profile the protein expression in S. maltophilia K279a, a completely sequenced clinical isolate, grown at 37 °C with respect to the strain grown at 26 °C. Among the proteins up-regulated at 37 °C, we identified GroEL, a molecular chaperone that mainly assist the folding and unfolding of proteins under both normal and stress conditions. A 2.4-kb groESL mRNA was detected independently by Northern blot analyses with a groES- and a groEL-specific probe, indicating that S. maltophilia groES and groEL form an operon. Primer extension analysis of S. maltophilia groESL done in Escherichia coli showed that 2 promoters, Pσ(32) and Pσ(70), were utilized under the heat-shock and normal condition, respectively, whereas S. maltophilia groEL was shown to act as a heat-shock gene at 37 °C, 42 °C, and, to a lesser extent, at 50 °C by real-time RT-PCR analyses. Finally, immunoblot analyses revealed that S. maltophilia GroEL strongly reacted with sera from CF patients chronically infected by the microorganism, but did not with sera from CF patients with sporadic infection or uninfected.
Istituto di Microbiologia, Università Cattolica del Sacro Cuore, Largo F. Vito, 1 00168 Rome, Italy.
Elena
E
De Carolis
Brunella
B
Posteraro
Ada Rita
AR
Florio
Bianca
B
Colonna
Gianni
G
Prosseda
Francesca
F
Bugli
Silvia Renzetti
SR
Lorenzetti
Ersilia
E
Fiscarelli
Rosanna
R
Inzitari
Federica
F
Iavarone
Massimo
M
Castagnola
Giovanni
G
Fadda
Maurizio
M
Sanguinetti
D001426:Bacterial Proteins / Q000096:biosynthesis*; D015152:Blotting, Northern; D018833:Chaperonins / Q000096:biosynthesis*; D015180:Electrophoresis, Gel, Two-Dimensional; D004926:Escherichia coli / Q000235:genetics; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial / Q000528:radiation effects*; D006801:Humans; D011401:Promoter Regions, Genetic; D020133:Reverse Transcriptase Polymerase Chain Reaction; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D020615:Stenotrophomonas maltophilia / Q000528:radiation effects*; D013696:Temperature
D001426:Bacterial Proteins; C097970:GroESL protein, Bacteria; D018833:Chaperonins