Molybdenum cofactor biosynthesis and its targeting into molybdoenzymes

The biosynthesis of the molybdenum cofactor (Moco) in bacteria involves the initial formation of cyclic pyranopterin monophosphate (cPMP) from 5’GTP, its conversion to molybdopterin (MPT), insertion of molybdenum into MPT (Mo-MPT), and further modification of Mo-MPT by the attachment of different nucleotides either forming the bis-molybdopterin dinucleotide cofactor (bis-MGD) or the molybdopterin cytosine dinucleotide cofactor (MCD). Bis-MGD and MCD can be further modified by the addition of a terminal sulfido ligand to the catalytic molybdenum site. After the synthesis of the Moco-variants, the specific form has to be targeted to the respective apo-enzyme by the aid of specific chaperones. The total goal of our studies is to identify novel factors in the biosynthesis of Moco which lead to its modification and stabilization in different bacteria.