4.6.1.17	(8S)-3',8-cyclo-7,8-dihydroguanosine 5'-P-CH2-PP	compound is converted to an analogue of the MoaC reaction intermediate and causes mechanism-based inhibition. the reaction product harbors an acid-labile triaminopyrimidinone base without an established pyranopterin structure and forms a tight complex with MoaC likely through a covalent linkage	228219