Biosynthesis of coenzyme F420 and methanopterin in Methanobacterium thermoautotrophicum: Studies with [1?-14C]adenosine

Factor F 0 and 7-methylpterin had approximately the same specific activities as the purine nucleotides. It follows that the ribityl side chain of factor F 0 is derived from the ribose side chain of a nucleotide precursor by reduction. The pyrazine ring of methanopterin is formed by ring expansion involving the ribose side chain of the precursor, GTP