ISSN:
1432-072X
Keywords:
Methanobacterium thermoautotrophicum
;
Coenzymes
;
Biosynthesis
;
Methanopterin
;
Factor F420
;
Deazaflavin
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract Growing cultures of Methanobacterium thermoautotrophicum were supplemented with [U-14C]adenosine or [1′-14C]adenosine. 7,8-Didemethyl-8-hydroxy-5-deazariboflavin (factor F0) and 7-methylpterin were isolated from the culture medium. Hydrolysis of cellular RNA yielded purine and pyrimidine nucleotides. The ribose side chain of proffered adenosine is efficiently incorporated into cellular adenosine and guanosine nucleotide pools but not into pyrimidine nucleotides. Thus, M. thermoautotrophicum can utilize exogenous adenosine by direct phosphorylation without hydrolysis of the glycosidic bond, and AMP can be efficiently converted to GMP. Factor F0 and 7-methylpterin had approximately the same specific activities as the purine nucleotides. It follows that the ribityl side chain of factor F0 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.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00249078
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