scholarly journals The Energetics of Molecular Adaptation in Transcriptional Regulation

2019 ◽  
Author(s):  
Griffin Chure ◽  
Manuel Razo-Mejia ◽  
Nathan M. Belliveau ◽  
Tal Einav ◽  
Zofii A. Kaczmarek ◽  
...  

Mutation is a critical mechanism by which evolution explores the functional landscape of proteins. Despite our ability to experimentally inflict mutations at will, it remains difficult to link sequence-level perturbations to systems-level responses. Here, we present a framework centered on measuring changes in the free energy of the system to link individual mutations in an allosteric transcriptional repressor to the parameters which govern its response. We find the energetic effects of the mutations can be categorized into several classes which have characteristic curves as a function of the inducer concentration. We experimentally test these diagnostic predictions using the well-characterized LacI repressor of Escherichia coli, probing several mutations in the DNA binding and inducer binding domains. We find that the change in gene expression due to a point mutation can be captured by modifying only a subset of the model parameters that describe the respective domain of the wild-type protein. These parameters appear to be insulated, with mutations in the DNA binding domain altering only the DNA affinity and those in the inducer binding domain altering only the allosteric parameters. Changing these subsets of parameters tunes the free energy of the system in a way that is concordant with theoretical expectations. Finally, we show that the induction profiles and resulting free energies associated with pairwise double mutants can be predicted with quantitative accuracy given knowledge of the single mutants, providing an avenue for identifying and quantifying epistatic interactions.SummaryWe present a biophysical model of allosteric transcriptional regulation that directly links the location of a mutation within a repressor to the biophysical parameters that describe its behavior. We explore the phenotypic space of a repressor with mutations in either the inducer binding or DNA binding domains. Using the LacI repressor in E. coli, we make sharp, falsifiable predictions and use this framework to generate a null hypothesis for how double mutants behave given knowledge of the single mutants. Linking mutations to the parameters which govern the system allows for quantitative predictions of how the free energy of the system changes as a result, permitting coarse graining of high-dimensional data into a single-parameter description of the mutational consequences.

2019 ◽  
Vol 116 (37) ◽  
pp. 18275-18284 ◽  
Author(s):  
Griffin Chure ◽  
Manuel Razo-Mejia ◽  
Nathan M. Belliveau ◽  
Tal Einav ◽  
Zofii A. Kaczmarek ◽  
...  

Mutation is a critical mechanism by which evolution explores the functional landscape of proteins. Despite our ability to experimentally inflict mutations at will, it remains difficult to link sequence-level perturbations to systems-level responses. Here, we present a framework centered on measuring changes in the free energy of the system to link individual mutations in an allosteric transcriptional repressor to the parameters which govern its response. We find that the energetic effects of the mutations can be categorized into several classes which have characteristic curves as a function of the inducer concentration. We experimentally test these diagnostic predictions using the well-characterized LacI repressor ofEscherichia coli, probing several mutations in the DNA binding and inducer binding domains. We find that the change in gene expression due to a point mutation can be captured by modifying only the model parameters that describe the respective domain of the wild-type protein. These parameters appear to be insulated, with mutations in the DNA binding domain altering only the DNA affinity and those in the inducer binding domain altering only the allosteric parameters. Changing these subsets of parameters tunes the free energy of the system in a way that is concordant with theoretical expectations. Finally, we show that the induction profiles and resulting free energies associated with pairwise double mutants can be predicted with quantitative accuracy given knowledge of the single mutants, providing an avenue for identifying and quantifying epistatic interactions.


Oncotarget ◽  
2018 ◽  
Vol 9 (40) ◽  
pp. 26144-26156 ◽  
Author(s):  
Hiroaki Taniguchi ◽  
Akihiro Fujimoto ◽  
Hidetoshi Kono ◽  
Mayuko Furuta ◽  
Masashi Fujita ◽  
...  

2019 ◽  
Vol 75 (a1) ◽  
pp. a203-a203
Author(s):  
Walter J. Chazin ◽  
Agnieszka M. Topolska-Woś ◽  
Norie Sugitani ◽  
John J. Cordoba ◽  
Hyun Suk Kim ◽  
...  

2001 ◽  
Vol 183 (9) ◽  
pp. 2947-2951 ◽  
Author(s):  
Douglas Hinerfeld ◽  
Gordon Churchward

ABSTRACT Purified integrase protein (Int) of the conjugative transposon Tn916 was shown, using nuclease protection experiments, to bind specifically to a site within the origin of conjugal transfer of the transposon, oriT. A sequence similar to the ends of the transposon that are bound by the C-terminal DNA-binding domain of Int was present in the protected region. However, Int binding tooriT required both the N- and C-terminal DNA-binding domains of Int, and the pattern of nuclease protection differed from that observed when Int binds to the transposon ends and flanking DNA. Binding of Int to oriT may be part of a mechanism to prevent premature conjugal transfer of Tn916 prior to excision from the donor DNA.


2004 ◽  
Vol 186 (11) ◽  
pp. 3499-3507 ◽  
Author(s):  
Hao Xu ◽  
Baohua Gu ◽  
B. Tracy Nixon ◽  
Timothy R. Hoover

ABSTRACT Activators of σ54-RNA polymerase holoenzyme couple ATP hydrolysis to formation of an open complex between the promoter and RNA polymerase. These activators are modular, consisting of an N-terminal regulatory domain, a C-terminal DNA-binding domain, and a central activation domain belonging to the AAA+ superfamily of ATPases. The AAA+ domain of Sinorhizobium meliloti C4-dicarboxylic acid transport protein D (DctD) is sufficient to activate transcription. Deletion analysis of the 3′ end of dctD identified the minimal functional C-terminal boundary of the AAA+ domain of DctD as being located between Gly-381 and Ala-384. Histidine-tagged versions of the DctD AAA+ domain were purified and characterized. The DctD AAA+ domain was significantly more soluble than DctD( Δ 1-142), a truncated DctD protein consisting of the AAA+ and DNA-binding domains. In addition, the DctD AAA+ domain was more homogeneous than DctD( Δ 1-142) when analyzed by native gel electrophoresis, migrating predominantly as a single high-molecular-weight species, while DctD( Δ 1-142) displayed multiple species. The DctD AAA+ domain, but not DctD( Δ 1-142), formed a stable complex with σ54 in the presence of the ATP transition state analogue ADP-aluminum fluoride. The DctD AAA+ domain activated transcription in vitro, but many of the transcripts appeared to terminate prematurely, suggesting that the DctD AAA+ domain interfered with transcription elongation. Thus, the DNA-binding domain of DctD appears to have roles in controlling the oligomerization of the AAA+ domain and modulating interactions with σ54 in addition to its role in recognition of upstream activation sequences.


Oncogene ◽  
2007 ◽  
Vol 26 (30) ◽  
pp. 4404-4414 ◽  
Author(s):  
M Morrow ◽  
A Samanta ◽  
D Kioussis ◽  
H J M Brady ◽  
O Williams

2012 ◽  
Vol 445 (3) ◽  
pp. 431-439 ◽  
Author(s):  
Michael A. Rieger ◽  
Tyler Duellman ◽  
Christopher Hooper ◽  
Magdalene Ameka ◽  
Joanna C. Bakowska ◽  
...  

MEKK1 [MAPK (mitogen-activated protein kinase)/ERK (extracellular-signal-regulated kinase) kinase kinase 1] is a MAP3K (MAPK kinase kinase) that regulates MAPK activation, and is the only known mammalian kinase that is also a ubiquitin ligase. MEKK1 contains a RING domain within its N-terminal regulatory region, and MEKK1 has been shown to ubiquitylate the AP-1 (activator protein 1) transcription factor protein c-Jun, but the mechanism by which MEKK1 interacts with c-Jun to induce ubiquitylation has not been defined. Proximal to the RING domain is a SWIM (SWI2/SNF2 and MuDR) domain of undetermined function. In the present study, we demonstrate that the MEKK1 SWIM domain, but not the RING domain, directly associates with the c-Jun DNA-binding domain, and that the SWIM domain is required for MEKK1-dependent c-Jun ubiquitylation. We further show that this MEKK1 SWIM–Jun interaction is specific, as SWIM domains from other proteins failed to bind c-Jun. We reveal that, although the Jun and Fos DNA-binding domains are highly conserved, the MEKK1 SWIM domain does not bind Fos. Finally, we identify the sequence unique to Jun proteins required for specific interaction with the MEKK1 SWIM domain. Therefore we propose that the MEKK1 SWIM domain represents a novel substrate-binding domain necessary for direct interaction between c-Jun and MEKK1 that promotes MEKK1-dependent c-Jun ubiquitylation.


2021 ◽  
Author(s):  
Mohamed Sobeh ◽  
Akio kitao

The dissociation process of the DNA binding domain of p53 (p53-DBD) from a DNA duplex that contains the consensus sequence, which is the specific target of p53-DBD, was investigated by a combination of dissociation parallel cascade selection molecular dynamics (dPaCS-MD) and the Markov state model (MSM). Based on an all-atom model including explicit solvent, we first simulated the p53-DBD dissociation processes by 75 trials of dPaCS-MD, which required an average simulation time of 11.2 ± 2.2 ns per trial. By setting the axis of the DNA duplex as the Z-axis and the binding side of p53-DBD on DNA as the + side of the X-axis, we found that dissociations took place along the +X and −Y directions (−Y directions) in 93% of the cases, while 7% of the cases moved along +X and +Y directions (+Y directions). Toward the −Y directions, p53-DBD dissociated first from the major groove and then detached from the minor groove, while unbinding from the minor groove occurred first in dissociations along the +Y directions. Analysis of the free energy landscape by MSM showed that loss of the minor groove interaction with p53-DBD toward the +Y directions incurred a relatively high energy cost (1.1 kcal/mol) upon a critical transition, whereas major groove detachment more frequently occurred with lower free energy costs. The standard binding free energy calculated from the free energy landscape was −10.9 ± 0.4 kcal/mol, which agrees with an experimental value of –11.1 kcal/mol. These results indicate that the dPaCS-MD/MSM combination can be a powerful tool to investigate dissociation mechanisms of two large molecules. Minor groove binding is mainly stabilized by R248, identified as the most important residue that tightly binds deep inside the minor groove. Analysis of the p53 key residues for DNA binding indicates high correlations with cancer-related mutations, confirming that impairment of the interactions between p53-DBD and DNA can be frequently related to cancer.


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