Activation of formylmethanofuran synthesis in cell extracts of Methanobacterium thermoautotrophicum.
In cell extracts of Methanobacterium thermoautotrophicum, formylmethanofuran (formyl-MFR) synthesis (an essential CO2 fixation reaction that is an early step in CO2 reduction to methane) is subject to a complex activation that involves a heterodisulfide of coenzyme M and N-(7-mercaptoheptanoyl)threonine O3-phosphate (CoM-S-S-HTP). In this paper we report that titanium(III) citrate, a low-potential reducing agent, stimulated CO2 reduction to methane and activated formyl-MFR synthesis in cell extracts. Titanium(III) citrate functioned as the sole source of electrons for formyl-MFR synthesis and enabled this reaction to occur independently of CoM-S-S-HTP. In addition, CoM-S-S-HTP was found to activate an unknown electron carrier that reduced metronidazole. The activation of formyl-MFR synthesis by CoM-S-S-HTP may involve the activation of a low-potential electron carrier.
Bobik
T A
TA
Department of Microbiology, University of Illinois, Urbana 61801.
Wolfe
R S
RS
D002474:Cell-Free System; D002851:Chromatography, High Pressure Liquid; D019605:Euryarchaeota / Q000378:metabolism*; D005663:Furans / Q000302:isolation & purification / Q000378:metabolism*; D007700:Kinetics; D008697:Methane / Q000032:analysis; D010084:Oxidation-Reduction
D005663:Furans; C050842:formylmethanofuran; D008697:Methane