5tw1

Crystal structure of a Mycobacterium smegmatis transcription initiation complex with RbpA

spinqualitylabelsall models 5tw1, resolution 2.76Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 5tw1 is a 11 chain structure with sequence from Aquifex aeolicus and Mycolicibacterium smegmatis MC2 155. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.76Å Ligands: EDO, MG, SO4, ZN Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function RBPA_MYCS2 Binds to RNA polymerase (RNAP), probably stimulating transcriptions from principal, but not alternative sigma factor promoters (By similarity). Partially restores transcription in the presence of rifampicin (Rif) in vitro; overexpression leads to an increase in the Rif tolerance in vivo, with smaller colonies. Seems to act by removing Rif from its binding site and preventing its further binding. No longer stimulates transcription in Rif-resistant RNA polymerase (with mutations in rpoB). Publication Abstract from PubMed RbpA and CarD are essential transcription regulators in mycobacteria. Mechanistic analyses of promoter open complex (RPo) formation establish thatRbpA and CarD cooperatively stimulate formation of anintermediate (RP2) leading to RPo; formation of RP2 islikely a bottleneck step at the majority of mycobacterial promoters. Once RPo forms, CarD also disfavors its isomerization back to RP2.We determined a 2.76 A-resolution crystal structure of a mycobacterial transcription initiation complex (TIC) with RbpA as well as a CarD/RbpA/TIC model. Both CarD and RbpA bind near the upstream edge of the -10 element where they likely facilitate DNA bending and impede transcription bubble collapse. In vivo studies demonstrate the essential role of RbpA, effects of RbpA truncations on transcription and cell physiology, and indicate additional functions for RbpA not evident in vitro. This work provides a framework to understand the control of mycobacterial transcriptionby RbpA and CarD. Structure and function of the mycobacterial transcription initiation complex with the essential regulator RbpA.,Hubin EA, Fay A, Xu C, Bean JM, Saecker RM, Glickman MS, Darst SA, Campbell EA Elife. 2017 Jan 9;6. pii: e22520. doi: 10.7554/eLife.22520. PMID:28067618 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Sigma factor 3D structures

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