Partial Purification and Characterization of Two Hydrogenases from the Extreme Thermophile Methanococcus jannaschii

AUTOR(ES)

Shah, Nilesh N.

RESUMO

F420-nonreactive and F420-reactive hydrogenases have been partially purified from Methanococcus jannaschii, an extremely thermophilic methanogen isolated from a submarine hydrothermal vent. The molecular weights of both hydrogenases were determined by native gradient electrophoresis in 5 to 27% polyacrylamide gels. The F420-nonreactive hydrogenase produced one major band (475 kilodaltons), whereas the F420-reactive hydrogenase produced two major bands (990 and 115 kilodaltons). The F420-nonreactive hydrogenase consisted of two subunits (43 and 31 kilodaltons), and the F420-reactive hydrogenase contained three subunits (48, 32, and 25 kilodaltons). Each hydrogenase was active at very high temperatures. Methyl viologen-reducing activity of the F420-nonreactive hydrogenase was maximal at 80°C but was still detectable at 103°C. The maximum activities of F420-reactive hydrogenase for F420 and methyl viologen were measured at 80 and 90°C, respectively. Low but measureable activity toward methyl viologen was repeatedly observed at 103°C. Moreover, the half-life of the F420-nonreactive hydrogenase at 70°C was over 9 h, and that of the F420-reactive enzyme was over 3 h.

Documentos Relacionados

• Pressure and Temperature Effects on Growth and Methane Production of the Extreme Thermophile Methanococcus jannaschii
• Purification and characterization of an inorganic pyrophosphatase from the extreme thermophile Thermus aquaticus.
• Pressure effects on the composition and thermal behavior of lipids from the deep-sea thermophile Methanococcus jannaschii.
• Identification and characterization of a DNA primase from the hyperthermophilic archaeon Methanococcus jannaschii.
• Methanococcus jannaschii Flap Endonuclease: Expression, Purification, and Substrate Requirements