Provided are astexin-1, astexin-2 and astexin-3 lasso peptides, which are based on sequences identified in Asticaccaulis excentricus, and methods of making and using same. Astexin-1 is highly polar, in contrast to many lasso peptides that are primarily hydrophobic, and has modest antimicrobial activity against Caulobacter crescentus, a bacterium related to Asticaccaulis excentricus. The solution structure of astexin-1 was determined, revealing a unique topology that is stabilized by hydrogen bonding between segments of the peptide. Astexins-2 and -3 are intracellular lasso peptides.
