Weinert Group in Nature Communications

Clip from the image RsbR haem pocket model and haem spectra." This image, and the article referenced, are licensed under a Creative Commons Attribution 4.0 International License.
Clip from the image RsbR haem pocket model and haem spectra.” This image, and the article referenced, are licensed under a Creative Commons Attribution 4.0 International License.

The Weinert Group has research featured in the June issue of Nature Communications. The paper, “An O2-sensing stressosome from a Gram-negative bacterium,” is co-authored by Xin Jia, Jian-bo Wang, Shannon Rivera, Duc Duong, and Emily E. Weinert.

Abstract:

Bacteria have evolved numerous pathways to sense and respond to changing environmental conditions, including, within Gram-positive bacteria, the stressosome complex that regulates transcription of general stress response genes. However, the signalling molecules recognized by Gram-positive stressosomes have yet to be identified, hindering our understanding of the signal transduction mechanism within the complex. Furthermore, an analogous pathway has yet to be described in Gram-negative bacteria. Here we characterize a putative stressosome from the Gram-negative bacterium Vibrio brasiliensis. The sensor protein RsbR binds haem and exhibits ligand-dependent control of the stressosome complex activity. Oxygen binding to the haem decreases activity, while ferrous RsbR results in increased activity, suggesting that the V. brasiliensis stressosome may be activated when the bacterium enters anaerobic growth conditions. The findings provide a model system for investigating ligand-dependent signalling within stressosome complexes, as well as insights into potential pathways controlled by oxygen-dependent signalling within Vibrio species.

[Full Article]

Collaborative study in Nature Communications Explores Recent Advances by Emory Scientists and International Colleagues

A recent study published in Nature Communications stems from an international collaboration between scientists in Emory’s own NSF Center for Selective C-H Functionalization and the Institute of Transformative Bio-Molecules (ITbM) at Nayoga University, Japan. The article “Decarbonylative organoboron cross-coupling of esters by nickel catalysis” details work that expands the scope of a Nobel Prize-winning carbon-carbon bond reaction. The expanded reaction uses aromatic esters and boronic acids as coupling partners in the presence of a nickel catalyst. The nickel catalyst is economically and environmentally friendly, making it strategically useful for pharmaceutical, agro-chemical, and organic materials applications.

The new research builds on the 2010 Nobel prize-winning Suzuki-Miyaura cross-coupling reaction, an extremely powerful strategy to synthesize a variety of significant organic compounds on an industrial scale. The reaction is usually catalyzed by a pallidium catalyst to couple boronic acids with organic hallides. The result is extremely powerful but its reaction partners can generate corrosive waste byproducts.

Researchers at ITbM and CCHF have demonstrated that readily available esters–carbonyl compounds found in fat and oils–can be used as alternative coupling partners, generating useful products such as derivatives of plant metabolites and a drug for treating hypertension, telmisartan.

Esters are known for their distinctive odors, such as banana and pineapple, thus making them a popular ingredient in perfumes. Due to their high commercial and synthetic accessibility, the use of esters to couple with boronic acids greatly expands the scope of available substrates for the Suzuki-Miyaura cross-coupling reaction.

Theoretical calculations conducted by Professor Djamaladdin Musaev, Director of the Emerson Center at Emory University, contributed valuable insight to the mechanism of the decarbonylative cross-coupling reaction between aromatic esters and boronic acids.

“This is a beautiful work in the frontier of organic transformations,” said Musaev. “I am grateful to Professor Itami and the entire ITbM team for providing the opportunity for us to contribute to this novel research project.”

In turn, Professor Ken Itami of ITbM praises Musaev for elucidating the unusual decarbonylative cross-coupling reaction. “This is obviously a result of the strong collaboration between ITbM and CCHF. We will continue to work together to conduct further optimization of the reaction system to expand its scope.”

Itami and his colleagues envisage that ongoing advances in this reaction method may lead to the development of new industrial processes for making biologically and structurally active compounds, including aliphatic esters.

Saliata Group published in Nature Communications

The Salaita Group recently published a paper in Nature Communications. The paper was subsequently highlighted in C&E News, Nature Reviews Molecular and Cell BiologyNature Methods, and Emory’s own eScience Commons

Zhang, Y.; Ge, C.; Zhu, C.; Salaita, K.; “DNA-based Digital Tension Probes Reveal Early Cell Adhesion Mechanics at the Single Molecule Level”, Nature Communications, 2014, 5, 5167.

[Journal link] [Manuscript PDF] [Supporting Information PDF] [SI movie 1] [SI movie 2] [SI movie 3] [SI movie 4].