Studies on the biosynthesis of coenzyme F420in methanogenic bacteria

✍ Scribed by Rolf Jaenchen; Peter Schönheit; Rudolf K. Thauer

• Publisher: Springer
• Year: 1984
• Tongue: English
• Weight: 420 KB
• Volume: 137
• Category: Article
• ISSN: 0302-8933
• DOI: 10.1007/bf00410735

✦ Synopsis

Coenzyme F42o is a 8-hydroxy-5-deazaflavin present in methanogenic bacteria. We have investigated whether the pyrimidine ring of the deazaflavin originates from guanine as in flavin biosynthesis, in which the pyrimidine ring of guanine is conserved. For this purpose the incorporation of [2-14C]guanine and of [8-14C]guanine into F4zo by growing cultures of Methanobacterium thermoautotrophicum was studied. Only in the case of [2-14C]guanine did F~z0 become labeled. The specific radioactivity of the deazaflavin and of guanine isolated from nucleic acids of [2-~4C]guanine grown cells were identical. This finding suggests that the pyrimidine ring of the deazaflavin and of flavins are synthesized by the same pathway.

F4z0 did not become labeled when M. thermoauto- trophicum was grown in the presence of methyl-[~4C] methionine, [U-14C]phenylalanine or [U-14C]tyrosine. This excludes that C-5 of the deazaflavin is derived from the methyl group ofmethionine and that the benzene ring comes from phenylalanine or tyrosine.