Robust growth on uridine at 37°C requires the lon promoter mutation.

aAll grew on uridine at 37°C.bThe sroGm1 mutation is C3182707T and the sroGm2 mutation is A3182644G. Both are in stems of the riboswitch structure and would prevent base pairing.cThe orientation of insL in IS186 is indicated relative to the numbering system of MG1655.dThe nemR promoter mutations are the same as that in NCM4300. They are predicted to eliminate repression of the nemRA operon by NemR [3].eThe mutation is in the ribosome binding site for nemR.