Formylmethanofuran: tetrahydromethanopterin formyltransferase and N 5,N 10-methylenetetrahydromethanopterin dehydrogenase from the sulfate-reducing Archaeoglobus fulgidus: similarities with the enzymes from methanogenic Archaea

Abstract

The sulfate-reducing Archaeoglobus fulgidus contains a number of enzymes previously thought to be unique for methanogenic Archaea. The purification and properties of two of these enzymes, of formylmethanofuran: tetrahydromethanopterin formyltransferase and of N5,N10-methylenetetrahydromethanopterin dehydrogenase (coenzyme F420 dependent) are described here. A comparison of the N-terminal amino acid sequences and of other molecular properties with those of the respective enzymes from three methanogenic Archaea revealed a high degree of similarity.

Physiology, Biochemistry, and Applications of F420- and Fo-Dependent Redox Reactions

“…Homologs of Mtd and Mer are also present in sulfate-reducing archaea (299,300). Archaeoglobus fulgidus converts lactate to three molecules of carbon dioxide using an Mtd/Mer-facilitated 1C pathway similar to methylotrophic methanogenesis (133, 300).…”

Methanogenesis: genes, genomes, and who's on first?

“…2) (53, 87, 118). These enzymes are, however, used to catalyze this portion of the pathway in the reverse direction, oxidizing methyl groups to CO 2 and thereby generating reduced cofactor F 420 (87). The MCH tree is not inconsistent with the ssu-rRNA tree, but more MCH sequences are needed for a valid comparison of the two trees.…”

Si‐face stereospecificity at C5 of coenzyme F420 for F420‐dependent N5,N10‐methylenetetrahydromethanopterin dehydrogenase, F420‐dependent N5,N10‐methylenetetrahydromethanopterin reductase and F420H2:dimethylnaphthoquinone oxidoreductase

“…F,,,-dependent methylene-&MPT dehydrogenase activity was determined at pH5.5 and 60°C by monitoring the formation of NS,"o-methenyl-&MPT+ (CH=&MPT+) from CH,=H,MPT photometrically at 335 nm (E = 21.6 mM-' cm-') (Schworer et al, 1993).…”

“…F,,,-dependent methylene-&MPT dehydrogenase was purified from A. fulgidus as described by Schworer et al (1993), F,,,-dependent methylene-H,Mm reductase was Purified from A. fulgidus as described by Schmitz et (1991) and F,,,-reducing hydrogenase was Purified from M. themoaufotroPhicum as described (1987) and Hedderich et a]. (1992).…”

“…The enzymes investigated are W,Wo-methylenetetrahydromethanopterin dehydrogenase, N5JITo-methylenetetrahydromethanopterin reductase and F , d , : dimethylnaphthoquinone oxidoreductase (F42a2 dehydrogenase). The function of these enzymes in the metabolism of the sulfate-reducing hyperthermophilic Archaeon is referred to in a recent study by Schworer et al (1993). completely devoid of F,,,-dependent methylene-H,MPT dehydrogenase and of F4,-dependent methylene-H4MPT reductase activity.…”