The histidine-phosphocarrier protein of the phosphoenolpyruvate: sugar phosphotransferase system of Bacillus sphaericus self-associates

DOMENECH, R.; HERNÁNDEZ-CIFRE, J.G.; BACARIZO, J.; DIEZ-PEÑA, A.I.; MARTÍNEZ-RODRÍGUEZ, S.; CAVASOTTO, CLAUDIO N.; GARCÍA DE LA TORRE, J.; CÁMARA-ARTIGÁS, A.; VELÁZQUEZ-CAMPOY, ADRIÁN; NEIRA, JOSE L.

PLOS ONE

PUBLIC LIBRARY SCIENCE

Lugar: San Francisco; Año: 2013 vol. 8 p. 69307 - 69307

1932-6203

The phosphotransferase system (PTS) is involved in the use of carbon sources inbacteria. Bacillus sphaericus, a bacterium with the ability to produce insecticidalproteins, is unable to use hexoses and pentoses as the sole carbon source, but it hasptsHI genes encoding the two general proteins of the PTS: enzyme I (EI) and thehistidine phosphocarrier (HPr). In this work, we describe the biophysical and structuralproperties of HPr from B. sphaericus, HPrbs, and its affinity towards EI of other speciesto find out whether there is inter-species binding. Conversely to what happens to othermembers of the HPr family, HPrbs forms several self-associated species. Theconformational stability of the protein is low, and it unfolds irreversibly during heating.The protein binds to the N-terminal domain of EI from Streptomyces coelicolor, EINsc,with a higher affinity than that of the natural partner of EINsc, HPrsc. Modelling of thecomplex between EINsc and HPrbs suggests that binding occurs similarly to thatobserved in other HPr species. We discuss the functional implications of the oligomericstates of HPrbs for the glycolytic activity of B. sphaericus, as well as a strategy toinhibit binding between HPrsc and EINsc.