1
|
Ye F, Gao F, Liu X, Buck M, Zhang X. Mechanisms of DNA opening revealed in AAA+ transcription complex structures. SCIENCE ADVANCES 2022; 8:eadd3479. [PMID: 36542713 PMCID: PMC9770992 DOI: 10.1126/sciadv.add3479] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Accepted: 11/07/2022] [Indexed: 06/17/2023]
Abstract
Gene transcription is carried out by RNA polymerase (RNAP) and requires the conversion of the initial closed promoter complex, where DNA is double stranded, to a transcription-competent open promoter complex, where DNA is opened up. In bacteria, RNAP relies on σ factors for its promoter specificities. Using a special form of sigma factor (σ54), which forms a stable closed complex and requires its activator that belongs to the AAA+ ATPases (ATPases associated with diverse cellular activities), we obtained cryo-electron microscopy structures of transcription initiation complexes that reveal a previously unidentified process of DNA melting opening. The σ54 amino terminus threads through the locally opened up DNA and then becomes enclosed by the AAA+ hexameric ring in the activator-bound intermediate complex. Our structures suggest how ATP hydrolysis by the AAA+ activator could remove the σ54 inhibition while helping to open up DNA, using σ54 amino-terminal peptide as a pry bar.
Collapse
Affiliation(s)
- Fuzhou Ye
- Section of Structural and Synthetic Biology, Department of Infectious Disease, Faculty of Medicine, Imperial College London, South Kensington SW7 2AZ, UK
| | - Forson Gao
- Section of Structural and Synthetic Biology, Department of Infectious Disease, Faculty of Medicine, Imperial College London, South Kensington SW7 2AZ, UK
| | - Xiaojiao Liu
- Section of Structural and Synthetic Biology, Department of Infectious Disease, Faculty of Medicine, Imperial College London, South Kensington SW7 2AZ, UK
| | - Martin Buck
- Department of Life Sciences, Imperial College London, South Kensington SW7 2AZ, UK
| | - Xiaodong Zhang
- Section of Structural and Synthetic Biology, Department of Infectious Disease, Faculty of Medicine, Imperial College London, South Kensington SW7 2AZ, UK
| |
Collapse
|
2
|
Zhou Y, Fujikura K, Mkrtchian S, Lauschke VM. Computational Methods for the Pharmacogenetic Interpretation of Next Generation Sequencing Data. Front Pharmacol 2018; 9:1437. [PMID: 30564131 PMCID: PMC6288784 DOI: 10.3389/fphar.2018.01437] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Accepted: 11/20/2018] [Indexed: 12/21/2022] Open
Abstract
Up to half of all patients do not respond to pharmacological treatment as intended. A substantial fraction of these inter-individual differences is due to heritable factors and a growing number of associations between genetic variations and drug response phenotypes have been identified. Importantly, the rapid progress in Next Generation Sequencing technologies in recent years unveiled the true complexity of the genetic landscape in pharmacogenes with tens of thousands of rare genetic variants. As each individual was found to harbor numerous such rare variants they are anticipated to be important contributors to the genetically encoded inter-individual variability in drug effects. The fundamental challenge however is their functional interpretation due to the sheer scale of the problem that renders systematic experimental characterization of these variants currently unfeasible. Here, we review concepts and important progress in the development of computational prediction methods that allow to evaluate the effect of amino acid sequence alterations in drug metabolizing enzymes and transporters. In addition, we discuss recent advances in the interpretation of functional effects of non-coding variants, such as variations in splice sites, regulatory regions and miRNA binding sites. We anticipate that these methodologies will provide a useful toolkit to facilitate the integration of the vast extent of rare genetic variability into drug response predictions in a precision medicine framework.
Collapse
Affiliation(s)
- Yitian Zhou
- Section of Pharmacogenetics, Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Kohei Fujikura
- Department of Diagnostic Pathology, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Souren Mkrtchian
- Section of Pharmacogenetics, Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Volker M. Lauschke
- Section of Pharmacogenetics, Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| |
Collapse
|
3
|
Analysis of Large-Scale Mutagenesis Data To Assess the Impact of Single Amino Acid Substitutions. Genetics 2017; 207:53-61. [PMID: 28751422 PMCID: PMC5586385 DOI: 10.1534/genetics.117.300064] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2017] [Accepted: 07/24/2017] [Indexed: 11/18/2022] Open
Abstract
Mutagenesis is a widely used method for identifying protein positions that are important for function or ligand binding. Advances in high-throughput DNA sequencing and mutagenesis techniques have enabled measurement of the effects of nearly all possible amino acid substitutions in many proteins. The resulting large-scale mutagenesis data sets offer a unique opportunity to draw general conclusions about the effects of different amino acid substitutions. Thus, we analyzed 34,373 mutations in 14 proteins whose effects were measured using large-scale mutagenesis approaches. Methionine was the most tolerated substitution, while proline was the least tolerated. We found that several substitutions, including histidine and asparagine, best recapitulated the effects of other substitutions, even when the identity of the wild-type amino acid was considered. The effects of histidine and asparagine substitutions also correlated best with the effects of other substitutions in different structural contexts. Furthermore, highly disruptive substitutions like aspartic and glutamic acid had the most discriminatory power for detecting ligand interface positions. Our work highlights the utility of large-scale mutagenesis data, and our conclusions can help guide future single substitution mutational scans.
Collapse
|
4
|
Moszyńska A, Gebert M, Collawn JF, Bartoszewski R. SNPs in microRNA target sites and their potential role in human disease. Open Biol 2017; 7:170019. [PMID: 28381629 PMCID: PMC5413909 DOI: 10.1098/rsob.170019] [Citation(s) in RCA: 140] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2017] [Accepted: 03/08/2017] [Indexed: 12/14/2022] Open
Abstract
In the post-genomic era, the goal of personalized medicine is to determine the correlation between genotype and phenotype. Developing high-throughput genotyping technologies such as genome-wide association studies (GWAS) and the 1000 Genomes Project (http://www.internationalgenome.org/about/#1000G_PROJECT) has dramatically enhanced our ability to map where changes in the genome occur on a population level by identifying millions of single nucleotide polymorphisms (SNPs). Polymorphisms, particularly those within the coding regions of proteins and at splice junctions, have received the most attention, but it is also now clear that polymorphisms in the non-coding regions are important. In these non-coding regions, the enhancer and promoter regions have received the most attention, whereas the 3'-UTR regions have until recently been overlooked. In this review, we examine how SNPs affect microRNA-binding sites in these regions, and how mRNA stability changes can lead to disease pathogenesis.
Collapse
Affiliation(s)
- Adrianna Moszyńska
- Department of Biology and Pharmaceutical Botany, Medical University of Gdansk, Gdansk, Poland
| | - Magdalena Gebert
- Department of Biology and Pharmaceutical Botany, Medical University of Gdansk, Gdansk, Poland
| | - James F Collawn
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Rafał Bartoszewski
- Department of Biology and Pharmaceutical Botany, Medical University of Gdansk, Gdansk, Poland
| |
Collapse
|
5
|
Siegel AR, Wemmer DE. Role of the σ 54 Activator Interacting Domain in Bacterial Transcription Initiation. J Mol Biol 2016; 428:4669-4685. [PMID: 27732872 DOI: 10.1016/j.jmb.2016.10.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Revised: 10/03/2016] [Accepted: 10/04/2016] [Indexed: 01/05/2023]
Abstract
Bacterial sigma factors are subunits of RNA polymerase that direct the holoenzyme to specific sets of promoters in the genome and are a central element of regulating transcription. Most polymerase holoenzymes open the promoter and initiate transcription rapidly after binding. However, polymerase containing the members of the σ54 family must be acted on by a transcriptional activator before DNA opening and initiation occur. A key domain in these transcriptional activators forms a hexameric AAA+ ATPase that acts through conformational changes brought on by ATP hydrolysis. Contacts between the transcriptional activator and σ54 are primarily made through an N-terminal σ54 activator interacting domain (AID). To better understand this mechanism of bacterial transcription initiation, we characterized the σ54 AID by NMR spectroscopy and other biophysical methods and show that it is an intrinsically disordered domain in σ54 alone. We identified a minimal construct of the Aquifex aeolicus σ54 AID that consists of two predicted helices and retains native-like binding affinity for the transcriptional activator NtrC1. Using the NtrC1 ATPase domain, bound with the non-hydrolyzable ATP analog ADP-beryllium fluoride, we studied the NtrC1-σ54 AID complex using NMR spectroscopy. We show that the σ54 AID becomes structured after associating with the core loops of the transcriptional activators in their ATP state and that the primary site of the interaction is the first predicted helix. Understanding this complex, formed as the first step toward initiation, will help unravel the mechanism of σ54 bacterial transcription initiation.
Collapse
Affiliation(s)
- Alexander R Siegel
- Biophysics Graduate Group, University of California, Berkeley, CA 94720, USA
| | - David E Wemmer
- Biophysics Graduate Group, University of California, Berkeley, CA 94720, USA; Department of Chemistry, University of California, Berkeley, CA 94720, USA.
| |
Collapse
|
6
|
Samuels DJ, Frye JG, Porwollik S, McClelland M, Mrázek J, Hoover TR, Karls AC. Use of a promiscuous, constitutively-active bacterial enhancer-binding protein to define the σ⁵⁴ (RpoN) regulon of Salmonella Typhimurium LT2. BMC Genomics 2013; 14:602. [PMID: 24007446 PMCID: PMC3844500 DOI: 10.1186/1471-2164-14-602] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2013] [Accepted: 08/28/2013] [Indexed: 11/10/2022] Open
Abstract
Background Sigma54, or RpoN, is an alternative σ factor found widely in eubacteria. A significant complication in analysis of the global σ54 regulon in a bacterium is that the σ54 RNA polymerase holoenzyme requires interaction with an active bacterial enhancer-binding protein (bEBP) to initiate transcription at a σ54-dependent promoter. Many bacteria possess multiple bEBPs, which are activated by diverse environmental stimuli. In this work, we assess the ability of a promiscuous, constitutively-active bEBP—the AAA+ ATPase domain of DctD from Sinorhizobium meliloti—to activate transcription from all σ54-dependent promoters for the characterization of the σ54 regulon of Salmonella Typhimurium LT2. Results The AAA+ ATPase domain of DctD was able to drive transcription from nearly all previously characterized or predicted σ54-dependent promoters in Salmonella under a single condition. These promoters are controlled by a variety of native activators and, under the condition tested, are not transcribed in the absence of the DctD AAA+ ATPase domain. We also identified a novel σ54-dependent promoter upstream of STM2939, a homolog of the cas1 component of a CRISPR system. ChIP-chip analysis revealed at least 70 σ54 binding sites in the chromosome, of which 58% are located within coding sequences. Promoter-lacZ fusions with selected intragenic σ54 binding sites suggest that many of these sites are capable of functioning as σ54-dependent promoters. Conclusion Since the DctD AAA+ ATPase domain proved effective in activating transcription from the diverse σ54-dependent promoters of the S. Typhimurium LT2 σ54 regulon under a single growth condition, this approach is likely to be valuable for examining σ54 regulons in other bacterial species. The S. Typhimurium σ54 regulon included a high number of intragenic σ54 binding sites/promoters, suggesting that σ54 may have multiple regulatory roles beyond the initiation of transcription at the start of an operon.
Collapse
Affiliation(s)
- David J Samuels
- Department of Microbiology, University of Georgia, 30602, Athens, GA, USA.
| | | | | | | | | | | | | |
Collapse
|
7
|
Affiliation(s)
- Robert O J Weinzierl
- Department of Life Sciences, Division of Biomolecular Sciences, Imperial College London , Sir Alexander Fleming Building, Exhibition Road, London SW7 2AZ, United Kingdom
| |
Collapse
|
8
|
Francke C, Groot Kormelink T, Hagemeijer Y, Overmars L, Sluijter V, Moezelaar R, Siezen RJ. Comparative analyses imply that the enigmatic Sigma factor 54 is a central controller of the bacterial exterior. BMC Genomics 2011; 12:385. [PMID: 21806785 PMCID: PMC3162934 DOI: 10.1186/1471-2164-12-385] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2011] [Accepted: 08/01/2011] [Indexed: 02/06/2023] Open
Abstract
Background Sigma-54 is a central regulator in many pathogenic bacteria and has been linked to a multitude of cellular processes like nitrogen assimilation and important functional traits such as motility, virulence, and biofilm formation. Until now it has remained obscure whether these phenomena and the control by Sigma-54 share an underlying theme. Results We have uncovered the commonality by performing a range of comparative genome analyses. A) The presence of Sigma-54 and its associated activators was determined for all sequenced prokaryotes. We observed a phylum-dependent distribution that is suggestive of an evolutionary relationship between Sigma-54 and lipopolysaccharide and flagellar biosynthesis. B) All Sigma-54 activators were identified and annotated. The relation with phosphotransfer-mediated signaling (TCS and PTS) and the transport and assimilation of carboxylates and nitrogen containing metabolites was substantiated. C) The function annotations, that were represented within the genomic context of all genes encoding Sigma-54, its activators and its promoters, were analyzed for intra-phylum representation and inter-phylum conservation. Promoters were localized using a straightforward scoring strategy that was formulated to identify similar motifs. We found clear highly-represented and conserved genetic associations with genes that concern the transport and biosynthesis of the metabolic intermediates of exopolysaccharides, flagella, lipids, lipopolysaccharides, lipoproteins and peptidoglycan. Conclusion Our analyses directly implicate Sigma-54 as a central player in the control over the processes that involve the physical interaction of an organism with its environment like in the colonization of a host (virulence) or the formation of biofilm.
Collapse
Affiliation(s)
- Christof Francke
- TI Food and Nutrition, P,O,Box 557, 6700AN Wageningen, The Netherlands.
| | | | | | | | | | | | | |
Collapse
|