Acts as a positive transcriptional regulator of the molybdopterin biosynthesis moa1 locus, promoting the expression of the moaA1B1C1D1 genes. Identification of single-nucleotide polymorphisms (SNPs) between the attenuated M.bovis BCG Pasteur strain and the virulent M.bovis strain AF2122/97 revealed a E159G mutation in BCG_3145. The E159G SNP was found to be present in all BCG strains, but absent from virulent M.bovis and Mycobacterium tuberculosis strains. The SNP in BCG_3145 was found to have a subtle effect on the activity of MoaR1, suggesting that this mutation is not a key event in the virulence attenuation of BCG. Belongs to the AfsR/DnrI/RedD regulatory family. Truncated N-terminus.