Induced α-Helix Structure in the Aryl Hydrocarbon Receptor Transactivation Domain Modulates Protein−Protein Interactions†

Biochemistry ◽  
2005 ◽  
Vol 44 (2) ◽  
pp. 734-743 ◽  
Author(s):  
Kate Watt ◽  
Thomas J. Jess ◽  
Sharon M. Kelly ◽  
Nicholas C. Price ◽  
Iain J. McEwan
2003 ◽  
Vol 31 (5) ◽  
pp. 1042-1046 ◽  
Author(s):  
J. Reid ◽  
R. Betney ◽  
K. Watt ◽  
I.J. McEwan

The AR (androgen receptor) belongs to the nuclear receptor superfamily and directly regulates patterns of gene expression in response to the steroids testosterone and dihydrotestosterone. Sequences within the large N-terminal domain of the receptor have been shown to be important for transactivation and protein–protein interactions; however, little is known about the structure and folding of this region. Folding of the AR transactivation domain was observed in the presence of the helix-stabilizing solvent trifluorethanol and the natural osmolyte TMAO (trimethylamine N-oxide). TMAO resulted in the movement of two tryptophan residues to a less solvent-exposed environment and the formation of a protease-resistant conformation. Critically, binding to a target protein, the RAP74 subunit of the general transcription factor TFIIF, resulted in a similar resistance to protease digestion, consistent with induced folding of the receptor transactivation domain. Our current hypothesis is that the folding of the transactivation domain in response to specific protein–protein interactions creates a platform for subsequent interactions, resulting in the formation of a competent transcriptional activation complex.


2017 ◽  
Vol 32 (2) ◽  
pp. 109-120 ◽  
Author(s):  
Cassie Jaeger ◽  
Ali Q. Khazaal ◽  
Canxin Xu ◽  
Mingwei Sun ◽  
Stacey L. Krager ◽  
...  

PAS domain–containing proteins can act as environmental sensors that capture external stimuli to allow coordination of organismal physiology with the outside world. These proteins permit diverse ligand binding and heterodimeric partnership, allowing for varied combinations of PAS-dependent protein-protein interactions and promoting crosstalk among signaling pathways. Previous studies report crosstalk between circadian clock proteins and the aryl hydrocarbon receptor (AhR). Activated AhR forms a heterodimer with the circadian clock protein Bmal1 and thereby functionally inhibits CLOCK/Bmal1 activity. If physiological activation of AhR through naturally occurring, endogenous ligands inhibits clock function, it seems plausible to hypothesize that decreased AhR expression releases AhR-induced inhibition of circadian rhythms. Because both AhR and the clock are important regulators of glucose metabolism, it follows that decreased AhR will also alter metabolic function. To test this hypothesis, rhythms of behavior, metabolic outputs, and circadian and metabolic gene expression were measured in AhR-deficient mice. Genetic depletion of AhR enhanced behavioral responses to changes in the light-dark cycle, increased rhythmic amplitude of circadian clock genes in the liver, and altered rhythms of glucose and insulin. This study provides evidence of AhR-induced inhibition that influences circadian rhythm amplitude.


2021 ◽  
Author(s):  
Hongshuang Wang ◽  
Robert S. Dawber ◽  
Peiyu Zhang ◽  
Martin Walko ◽  
Andrew J. Wilson ◽  
...  

This review summarizes the influence of inserting constraints on biophysical, conformational, structural and cellular behaviour for peptides targeting α-helix mediated protein–protein interactions.


2013 ◽  
Vol 224 (1) ◽  
pp. 13-24 ◽  
Author(s):  
Adam M. Reitzel ◽  
Yale J. Passamaneck ◽  
Sibel I. Karchner ◽  
Diana G. Franks ◽  
Mark Q. Martindale ◽  
...  

2002 ◽  
Vol 184 (18) ◽  
pp. 5200-5203 ◽  
Author(s):  
Eun Hee Cho ◽  
Richard I. Gumport ◽  
Jeffrey F. Gardner

ABSTRACT Bacteriophage lambda site-specific recombination comprises two overall reactions, integration into and excision from the host chromosome. Lambda integrase (Int) carries out both reactions. During excision, excisionase (Xis) helps Int to bind DNA and introduces a bend in the DNA that facilitates formation of the proper excisive nucleoprotein complex. The carboxyl-terminal α-helix of Xis is thought to interact with Int through direct protein-protein interactions. In this study, we used gel mobility shift assays to show that the amino-terminal domain of Int maintained cooperative interactions with Xis. This finding indicates that the amino-terminal arm-type DNA binding domain of Int interacts with Xis.


2020 ◽  
Author(s):  
Johanne Mbianda ◽  
May Bakail ◽  
Christophe André ◽  
Gwenaëlle Moal ◽  
Marie E. Perrin ◽  
...  

<p><b>Sequence-specific oligomers with predictable folding patterns, i.e. foldamers provide new opportunities to mimic α-helical peptides and design inhibitors of protein-protein interactions. One major hurdle of this strategy is to retain the correct orientation of key side chains involved in protein surface recognition. Here, we show that the structural plasticity of a foldamer backbone may significantly contribute to the required spatial adjustment for optimal interaction with the protein surface. By using oligoureas as α-helix mimics, we designed a foldamer/peptide hybrid inhibitor of histone chaperone ASF1, a key regulator of chromatin dynamics. The crystal structure of its complex with ASF1 reveals a striking plasticity of the urea backbone, which adapts to the ASF1 surface to maintain the same binding interface. One additional benefit of generating ASF1 ligands with non-peptide oligourea segments is the resistance to proteolysis in human plasma which was highly improved compared to the cognate α-helical peptide. </b></p>


2020 ◽  
Vol 63 (17) ◽  
pp. 10087-10087
Author(s):  
Peng Sang ◽  
Yan Shi ◽  
Junhao Lu ◽  
Lihong Chen ◽  
Leixiang Yang ◽  
...  

Microbiology ◽  
2000 ◽  
Vol 81 (1) ◽  
pp. 209-218 ◽  
Author(s):  
Mirriam G. J. Tacken ◽  
Peter J. M. Rottier ◽  
Arno L. J. Gielkens ◽  
Ben P. H. Peeters

Little is known about the intermolecular interactions between the viral proteins of infectious bursal disease virus (IBDV). By using the yeast two-hybrid system, which allows the detection of protein–protein interactions in vivo, all possible interactions were tested by fusing the viral proteins to the LexA DNA-binding domain and the B42 transactivation domain. A heterologous interaction between VP1 and VP3, and homologous interactions of pVP2, VP3, VP5 and possibly VP1, were found by co-expression of the fusion proteins in Saccharomyces cerevisiae. The presence of the VP1–VP3 complex in IBDV-infected cells was confirmed by co-immunoprecipitation studies. Kinetic analyses showed that the complex of VP1 and VP3 is formed in the cytoplasm and eventually is released into the cell-culture medium, indicating that VP1–VP3 complexes are present in mature virions. In IBDV-infected cells, VP1 was present in two forms of 90 and 95 kDa. Whereas VP3 initially interacted with both the 90 and 95 kDa proteins, later it interacted exclusively with the 95 kDa protein both in infected cells and in the culture supernatant. These results suggest that the VP1–VP3 complex is involved in replication and packaging of the IBDV genome.


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