Microbiology news and views
J. Mol. Micro. Biotechnol. 3: 429-432
Evidence for a Dimerisation State of the Bacillus subtilis Catabolite Repression HPr-Like Protein, Crh
François Penin, Adrien Favier, Roland Montserret, Bernhard Brutscher, Josef Deutscher, Dominique Marion and Anne Galinier
The Bacillus subtilis catabolite repression HPr (Crh) exhibits 45% sequence identity when compared to histidine-containing protein (HPr), a phosphocarrier protein of the phosphoenolpyruvate:carbohydrate phosphotransferase system. We report here that Crh preparations contain a mixture of monomers and homodimers, whereas HPr is known to be monomeric in solution. The dissociation rate of dimers is very slow (t1/2 of about 10 hours), and the percentage of dimers in Crh preparations increases with rising temperature or protein concentration. However, at temperatures above 25°C and a protein concentration of 10 mg/ml, Crh dimers slowly aggregate. Typically, NMR spectra recorded at 25°C showed the coexistence of both forms of Crh, while in Crh solutions kept at 35°C, almost exclusively Crh monomers could be detected. Circular dichroism analysis revealed that the monomeric and dimeric forms of Crh are well folded and exhibit the same overall structure. The physiological significance of the slow Crh monomer/dimer equilibrium remains enigmatic.
Full article [pdf]
New and forthcoming molecular biology books
Recommended Reading