the pathway of ergothioneine biosynthesis in mycobacteria , as judged by the use s ( 35 ) -sulfate and l-histidine-2-c ( 14 ) as tracers , appears similar to that found in neurospora crassa and claviceps purpurea , that is , from histidine to ergothioneine via hercynine .
C0019602
histidine
C0014713
ergothioneine