View source for 5tw1


==Crystal structure of a Mycobacterium smegmatis transcription initiation complex with RbpA==
<StructureSection load='5tw1' size='340' side='right' caption='[[5tw1]], [[Resolution|resolution]] 2.76&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[5tw1]] is a 11 chain structure with sequence from [http://en.wikipedia.org/wiki/Mycs2 Mycs2] and [http://en.wikipedia.org/wiki/Mycobacterium_smegmatis_str._mc2_155 Mycobacterium smegmatis str. mc2 155]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=5TW1 OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=5TW1 FirstGlance]. <br>
</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=EDO:1,2-ETHANEDIOL'>EDO</scene>, <scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene>, <scene name='pdbligand=SO4:SULFATE+ION'>SO4</scene>, <scene name='pdbligand=ZN:ZINC+ION'>ZN</scene></td></tr>
<tr id='NonStdRes'><td class="sblockLbl"><b>[[Non-Standard_Residue|NonStd Res:]]</b></td><td class="sblockDat"><scene name='pdbligand=UNK:UNKNOWN'>UNK</scene></td></tr>
<tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">rbpA, MSMEG_3858, MSMEI_3768 ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=246196 MYCS2]), rpoD, sigA, MSMEG_2758, MSMEI_2690 ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=246196 MYCS2])</td></tr>
<tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[http://en.wikipedia.org/wiki/DNA-directed_RNA_polymerase DNA-directed RNA polymerase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.7.7.6 2.7.7.6] </span></td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=5tw1 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=5tw1 OCA], [http://pdbe.org/5tw1 PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=5tw1 RCSB], [http://www.ebi.ac.uk/pdbsum/5tw1 PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=5tw1 ProSAT]</span></td></tr>
</table>
== Function ==
[[http://www.uniprot.org/uniprot/A0QW02_MYCS2 A0QW02_MYCS2]] Sigma factors are initiation factors that promote the attachment of RNA polymerase to specific initiation sites and are then released. This sigma factor is the primary sigma factor during exponential growth.[SAAS:SAAS00535554] [[http://www.uniprot.org/uniprot/RPOB_MYCS2 RPOB_MYCS2]] DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates. This subunit often mutates to generate rifampicin (Rif) resistance. Interaction with RbpA partially restores Rif-inhibited transcription; once the subunit is Rif-resistant however RbpA no longer stimulates transcription.[HAMAP-Rule:MF_01321]<ref>PMID:19926651</ref>  [[http://www.uniprot.org/uniprot/RPOA_MYCS2 RPOA_MYCS2]] DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates.[HAMAP-Rule:MF_00059]<ref>PMID:19926651</ref>  [[http://www.uniprot.org/uniprot/RBPA_MYCS2 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).<ref>PMID:19926651</ref> <ref>PMID:21415119</ref>  [[http://www.uniprot.org/uniprot/RPOC_MYCS2 RPOC_MYCS2]] DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates.[HAMAP-Rule:MF_01322]<ref>PMID:19926651</ref>  [[http://www.uniprot.org/uniprot/RPOZ_MYCS2 RPOZ_MYCS2]] Promotes RNA polymerase assembly. Latches the N- and C-terminal regions of the beta' subunit thereby facilitating its interaction with the beta and alpha subunits.[HAMAP-Rule:MF_00366]<ref>PMID:19926651</ref>  
<div style="background-color:#fffaf0;">
== 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<ref>PMID:28067618</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 5tw1" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: DNA-directed RNA polymerase]]
[[Category: Mycobacterium smegmatis str. mc2 155]]
[[Category: Mycs2]]
[[Category: Campbell, E A]]
[[Category: Darst, S A]]
[[Category: Hubin, E A]]
[[Category: Transcription activator-transferase-dna complex]]