HIPS Talk: „Structures of bacterial RNA polymerase in complex with inhibitors toward understandings of their mechanism of action, resistance and new antibiotic development “
Prof. Dr. Katsuhiko Murakami, Department of Biochemistry and Molecular Biology Pennsylvania State University will give a presentation entitled
Tuberculosis (TB) is one of the most significant global challenges to human health. For over four decades, Rifampin (Rif), a semi-synthetic derivative of Rifamycin, has been used as a first line antibiotic treatment of tuberculosis and is the cornerstone of current short-term tuberculosis treatment. The mode of action involves tight Rif binding to a beta subunit of bacterial RNA polymerase (Kd is sub nanomolar) to inhibit RNA transcription. Although many Rif resistant (RifR) strains with mutations in the Rif-binding pocket can be isolated in bacterial culture, only three specific RifR mutations account for over 80 % of Mycobacterium tuberculosis (MTB) RifR strains in clinical isolates due to RifR associated fitness costs.
Recently, we have shown that RNA polymerase from Escherichia coli can be prepared from a convenient overexpression system and its structure can be determined by X-ray crystallography. The E. coli RNA polymerase structural study has enabled us to further characterize bacterial RNA polymerase mutants including antibiotic-resistant RNA polymerases. In the current study, we have determined the X-ray crystal structures of the E. coli RNA polymerase RifR mutants each having one of three major RifR mutations found in clinical isolates. Each RifR RNA polymerase structure shows a unique conformation of the Rif binding pocket and their structural deviations from the wild-type Rif binding pocket are consistent with their Rif resistances suggesting that the RifR results from alternating the shape complementary between the Rif binding pocket and Rif rather than disrupting their hydrophilic and hydrophobic interactions. This study provides an important step for understanding the structure−activity relationship of Rif against RifR RNA polymerase inhibition and toward developing superior Rif analogues for RifR MTB.
Song, T. et al, (2014). Fitness costs of rifampicin-resistance in Mycobacterium tuberculosis are amplified under conditions of nutrient starvation and compensated by mutation in the β' subunit of RNA polymerase. Mol. Microbiol., on-line publication.
Molodtsov, V., I.N. Nawarathne, N.T. Scharf, P.D. Kirchhoff, H.D.H. Showalter, G.A. Garcia and K.S. Murakami (2013). X-ray crystal structures of the Escherichia coli RNA polymerase in complex with Benzoxazinorifamycins. J. Med. Chem. 56, 4758-4763.
Murakami, K.S. (2013). The X-ray crystal structure of Escherichia coli RNA polymerase Sigma70 Holoenzyme. J Biol Chem., 288, 9126-9134.
Universität des Saarlandes
Building and room
Blg E1.3, Lecture Hall 003
Prof. Dr. Katsuhiko Murakami,
Department of Biochemistry and Molecular Biology Pennsylvania State University
Prof. Dr. Rolf Hartmann
How to find us in Saarbrücken
The HIPS building is located at the east entrance on the main campus of Saarland University, which is situated outside the city centre of Saarbrücken, the state capital of Saarland. Saarland is located in the south-west of Germany, having common frontiers with Luxembourg and France.
Helmholtz-Institut für Pharmazeutische Forschung Saarland (HIPS)
Universitätscampus E8 1
- from the north (Cologne/Trier) via the motorway A1/A8 to „Autobahnkreuz Neunkirchen“, take A6 to „Saarbrücken“
- from the east (Kaiserslautern/Mannheim) via A6 to "Saarbrücken/Paris"
- from the north-west from Luxembourg via A620 by-pass the city centre and follow A6 to „Mannheim“
- from the west (Metz/Paris) and south-west (Strasbourg) via the A4/A320 (E50) follow A6 (E50) to „Mannheim“
- to reach the campus from motorway A6: take exit no. 5 „St. Ingbert West/Universität“, follow „Universität Ost“, (ca. 6 km)
(ICE/TGV and Intercity - Saarbrücken Central Station) you can reach the campus by local busses from the main train station (112, 124) and the city centre (101, 102, 109, 111) within 15 min
- HIPS at UdS Campus (pdf, 137 kB)