Structures of coenzyme F420 in Mycobacterium species

The structure of coenzyme F-420 in Mycobacterium smegmatis was examined using proton NMR, amino acid analysis, and HPLC. The two major F-420 structures were shown to be composed of a chromophore identical to that of F-420 from Methanobacterium thermoautotrophicum, with a side chain of a ribityl residue, a lactyl residue and five or six glutamate groups (F-420-5 and F-420-6). Peptidase treatment studies suggested that L.-glutamate groups are linked by gamma -glutamyl bonds in the side chain. HPLC analysis indicated that Mycobacterium tuberculosis, Mycobacterium bovis BCG, and Mycobacterium fortuitum have F-420-5 and F-420-6 as the predominant structures, whereas Mycobacterium avium contains F-420-5, F-420-6 and F-420-7 in significant amounts. 7,8-Didemethyl 8-hydroxy 5-deazariboflavin (FO), an intermediate in F-420 biosynthesis, accounted for about 1-7% of the total deazaflavin in cells. Peptidase treatment of F-420 created F-420 derivatives that may be useful for the assay of enzymes involved in F-420 biosynthesis.