Lariatins, novel anti-mycobacterial peptides with a lasso structure, produced by Rhodococcus jostii K01-B0171

Two anti-mycobacterial peptides with a lasso structure, named lariatins A and B, were separated by HP-20 and ODS column chromatographies and purified by HPLC from the culture broth of Rhodococcus jostii K01-B0171, which was isolated from soil aggregates collected in Yunnan, China. Lariains A and B showed growth inhibition against Mycobacterium smegmatis with MIC values of 3.13 and 6.25 mu g/ml in agar dilution method, respectively. Furthermore, lariatin A inhibited the growth of Mycobacterium tuberculosis with an MIC of 0.39 mu g/ml in liquid microdilution method.