Guanosine, folates

Mechanistic studies on the formation of the molybdopterin cofactor are still at an early stage. Conversion of guanosine, presumably as the triphosphate, to precursor Z occurs with retention of C-8 [84]. A possible mechanism for this third type of cyclohydrolase, which is consistent with the labeling experiment, is outlined in Fig. 20. (The other two types of cyclohydrolase are cyclohydrolase 1 for folate biosynthesis and cyclohydrolase II for riboflavin biosynthesis. In both cases, C8 is removed as formate.)... 

Biomolecules provide a variety of hydrogen-bonding components even for synthetic approaches. Recently, hydrogen-bonded assemblies of folate [75] and guanosine [76] have attracted much attention. Gottarelli and coworkers [77,78] reported that folic acid 16 self-assemble into tetra-mer, which form columnar structures in aqueous potassium salt solution (Figure 12). In this case, potassium cation promotes the formation of lyotropic columnar liquid-crystalline phase (Figure 12). 

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