Purification and characterization of a chlorite dismutase from Pseudomonas chloritidismutans
Mehboob, F. ; Wolterink, A.F.W.M. ; Vermeulen, A.J. ; Jiang, B. ; Hagedoorn, P.L. ; Stams, A.J.M. ; Kengen, S.W.M. - \ 2009
FEMS Microbiology Letters 293 (2009)1. - ISSN 0378-1097 - p. 115 - 121.
desulfovibrio-vulgaris hildenborough - (per)chlorate-reducing bacteria - strain gr-1 - reductase - catalase
The chlorite dismutase (Cld) of Pseudomonas chloritidismutans was purified from the periplasmic fraction in one step by hydroxyapatite chromatography. The enzyme has a molecular mass of 110 kDa and consists of four 31-kDa subunits. Enzyme catalysis followed Michaelis-Menten kinetics, with Vmax and K(m) values of 443 U mg(-1) and 84 microM, respectively. A pyridine-NaOH-dithionite-reduced Cld revealed a Soret peak at 418 nm, indicative for protoheme IX. The spectral data indicate the presence of 1.5 mol protoheme IX mol(-1) tetrameric enzyme while metal analysis revealed 2.2 mol iron mol(-1) tetrameric enzyme. High concentrations of chlorite resulted in the disappearance of the Soret peak, which coincided with loss in activity. Electron paramagnetic resonance analyses showed an axial high-spin ferric iron signal. Cld was inhibited by cyanide, azide, but not by hydroxylamine or 3-amino-1,2,3-triazole. Remarkably, the activity was drastically enhanced by kosmotropic salts, and chaotropic salts decreased the activity, in accordance with the Hofmeister series. Chlorite conversion in the presence of 18O-labeled water did not result in the formation of oxygen with a mass of 34 (16O-18O) or a mass of 36 ((18)O-(18)O), indicating that water is not a substrate in the reaction and that both oxygen atoms originate from chlorite
Novel baculovirus-derived p67 subunit vaccines efficacious against East Coast fever in cattle
Kaba, S.A. ; Musoke, A.J. ; Schaap, D. ; Schetters, T. ; Rowlands, J. ; Vermeulen, A.J. ; Nene, V. ; Vlak, J.M. ; Oers, M.M. van - \ 2005
Vaccine 23 (2005)21. - ISSN 0264-410X - p. 2791 - 2800.
theileria-parva sporozoites - neutralizing epitopes - monoclonal-antibody - surface-antigen - protection - protein - stocks - immunogenicity - immunization - leukocytes
Two novel baculovirus-derived recombinant Theileria parva p67 constructs were tested for their vaccine potential against East Coast fever. Boran calves were immunized with a his-GFP-p67 fusion protein (GFP:p67¿SS) or with GP64:p67C, a protein fusion between a C-terminal domain of p67 and the baculovirus envelope protein GP64. Both GFP:p67¿SS and GP64:p67C induced antibodies with high ELISA titers that neutralized T. parva sporozoites with high efficiency. Upon challenge, a correlation was observed between the in vitro neutralizing capacity and the reduction in severe ECF for individual animals. A protection level upto 85% was obtained. This level of protection was achieved with only two inoculations of 100 ¿g per dose, which is a major improvement over previous recombinant p67 products