To elucidate the mechanism used by this efflux system for multidrug recognition and extrusion, we here describe the crystal Miglitol structure of the inner membrane MtrD multidrug efflux pump. The findings reveal a novel structural feature that is not found in other known RND efflux pumps. Natural productshave been the major sources for clinical drug discovery and development for many decades. NPs with novel activities or skeletons are constantly needed to antagonize newly emerging threats to human health. In recent years, the explosion of genome sequencing has led to rapid development of novel NP screening approaches which have greatly increased the number and diversity of NPs inventories. As a correlation to this increase, understanding how the NPs are biosynthesized is also very important. Accessing to the mechanisms underlying NPs biosynthesis will not only improve our knowledge of various kinds of enzymatic reactions, but also pave the ways for future combinatorial biosynthesis which can guide medicinal chemistry in developing more applicable NP-derived drugs. Adequate structural information of biosynthesis intermediates or analogs is generally required to establish an unambiguous biosynthetic pathway for a particular NP. However, due to the low concentrations or insignificant bio-activities of individual candidates or insufficient speculation on the candidates’ structures, potential intermediates and analogs accumulated in the fermentation culture of the producing strain were often overlooked in liquid chromatographyand mass spectrometryanalysis.Therefore, the progress toward revealing the NPs’ biosynthetic 
mechanisms has significantly lagged behind those toward NP discovery and screening, thus prompting the need for effective solutions. Pyrrolamides, biosynthesized by Streptomyces and related actinobacteria, are a class of poly-pyrrolic natural products containing one or more pyrrole-2-carboxamide moieties in their structures. Most pyrrolamides, including congocidine, distamycin, and pyrronamycin B, are found to possess the ability to bind to specific DNA sequences, which enables this compound group with many desirable biological activities. Although the discovered natural pyrrolamides are still too toxic for clinical use, these molecules are still attractive in the field of pharmacology because their selective DNA sequence binding features may inspire the development of special drugs. Additionally, numerous efforts have been made to Gentamycin Sulfate chemically synthesize several DNA-binding agents based on pyrrolamide structures. Thus, exploring novel NPs belonging to the pyrrolamide family can provide more skeleton hints to current DNA-binding pharmaceutical research. Recently, the first pyrrolamide gene cluster directing congocidine biosynthesis is identified in Streptomyces ambofaciens. Juguet et al. demonstrated that congocidine is assembled by an iterative nonribosomal peptide synthetase. In another work, nearly every gene in the congocidine gene cluster is separately inactivated, and LCMS analysis of the related mutants showed that 4-acetamidopyrrole-2-carboxylate is the key precursor for pyrrolamide biosynthesis. However, the main mechanism underlying the control of pyrrole polymerization, which may be the most intriguing question in oligo-pyrroles NP biosynthesis.