Biophysics

Dynamic basis of lipopolysaccharide export by LptB2FGC

1. Marina Dajka
2. Tobias Rath
3. Nina Morgner
4. Benesh Joseph

• Curated by eLife

  eLife assessment

  This study provides an important advance in the molecular understanding of the lipopolysaccharide export mechanism and machinery in bacteria. By using advanced spectroscopy approaches, the experiments provide convincing biophysical support for the dynamic behavior of the multisubunit Lpt transport system. This work has implications for understanding bacterial cell envelope biogenesis and developing drugs that target Gram negative pathogens.

Reviewed by eLife

Single turnover transient state kinetics reveals processive protein unfolding catalyzed by Escherichia coli ClpB

1. Jaskamaljot Kaur Banwait
2. Liana Islam
3. Aaron L Lucius

• Curated by eLife

  eLife assessment

  This valuable study presents the development of a single turnover stopped-flow fluorescence experiment to study the kinetics of substrate unfolding and translocation by the bacterial ClpB disaggregase. Using non-physiological nucleotides to bypass the physiological regulation mechanism of ClpB, the authors convincingly show that the ClpB disaggregase is a processive motor with a slow unfolding step preceding rapid translocation. The results of this analysis are of value for future mechanistic studies on energy-dependent unfolding, degradation, and disaggregation molecular machines.

Reviewed by eLife

Should I stay or should I go? Spatio-temporal dynamics of bacterial biofilms in confined flows

1. Massinissa Benbelkacem
2. Gabriel Ramos
3. Fatima El Garah
4. Yara Abidine
5. Christine Roques
6. Yohan Davit

• Curated by eLife

  eLife assessment

  This important study integrates microfluidic experiments and mathematical modeling to investigate how flow dynamics and biofilm growth and detachment influence each other. Using Pseudomonas aeruginosa as a model organism, the study identifies several key effects and stages in biofilm development, albeit with some weaknesses in clearly defining the setup and some of their interpretations. The comparison between experimental results and theoretical models is convincing, providing a robust analysis of the biofilm's behavior under varying flow conditions. The findings will be helpful for researchers working on biofilms and their applications.

Reviewed by eLife

Robust optogenetic inhibition with red-light-sensitive anion-conducting channelrhodopsins

1. Johannes Oppermann
2. Andrey Rozenberg
3. Thomaz Fabrin
4. Cristian González-Cabrera
5. Rafael Parker
6. Oded Béjà
7. Matthias Prigge
8. Peter Hegemann

• Curated by eLife

  eLife assessment

  This important study describes the discovery and further engineering of a red light-activated, chloride-conducting Channelrhodopsin (ACR) that could be used to inhibit neuronal activity. The evidence for the spectral confirmation and biophysical characterization of MsACR and raACR, and ion selectivity are solid; however, the evidence supporting the use of the tools in vivo is incomplete and missing proper controls. In addition, benchmarking against other inhibitory tools is somewhat missing. With the in vivo part strengthened, this paper would interest neuroscientists seeking more efficient ways to inhibit neuronal activity.

Reviewed by eLife

The exchange dynamics of biomolecular condensates

1. Yaojun Zhang
2. Andrew GT Pyo
3. Ross Kliegman
4. Yoyo Jiang
5. Clifford P Brangwynne
6. Howard A Stone
7. Ned S Wingreen

• Curated by eLife

  eLife assessment

  This valuable contribution studies factors that impact molecular exchange between dense and dilute phases of biomolecular condensates through continuum models and coarse-grained simulations. The authors provide convincing evidence that interfacial resistance can cause molecules to bounce off the interface and limit mixing. Results like these can inform how experimental results in the field of biological condensates are interpreted.

Reviewed by eLife

The actin cortex acts as a mechanical memory of morphology in confined migrating cells

1. Yohalie Kalukula
2. Marine Luciano
3. Gleb Simanov
4. Guillaume Charras
5. David B. Brückner
6. Sylvain Gabriele

Reviewed by preLights

Revealing a hidden conducting state by manipulating the intracellular domains in KV10.1 exposes the coupling between two gating mechanisms

1. Reham Abdelaziz
2. Adam P Tomczak
3. Andreas Neef
4. Luis A Pardo

• Curated by eLife

  eLife assessment

  This valuable study examines the role of the interaction between cytoplasmic N- and C-terminal domains in voltage-dependent gating of Kv10.1 channels. The authors suggest that they have identified a hidden open state in Kv10.1 mutant channels, thus providing a window for observing early conformational transitions associated with channel gating. The evidence supporting the major conclusions is solid, but additional work is required to determine the molecular mechanism underlying the observations in this study. Learning the molecular mechanisms could be significant in understanding the gating mechanisms of the KCNH family and will appeal to biophysicists interested in ion channels and physiologists interested in cancer biology.

Reviewed by eLife

Stochastic tug-of-war among sarcomeres mediates cardiomyocyte response to environmental stiffness

1. Daniel Haertter
2. Lara Hauke
3. Til Driehorst
4. Kengo Nishi
5. Wolfram-Hubertus Zimmermann
6. Christoph F Schmidt

• Curated by eLife

  eLife assessment

  This study provides a valuable characterization of individual sarcomere's contractility and synchrony in spontaneously beating cardiomyocytes as a function of substrate stiffness. The authors, however, provide an incomplete explanation for the observed heterogeneous and stochastic dynamics, so that the work remains mainly descriptive. The work will be of interest to scientists working on muscle biophysics, nonlinear dynamics, and synchronization phenomena in biological systems.

Reviewed by eLife

On the pH-dependence of α-synuclein amyloid polymorphism and the role of secondary nucleation in seed-based amyloid propagation

1. Lukas Frey
2. Dhiman Ghosh
3. Bilal M Qureshi
4. David Rhyner
5. Ricardo Guerrero-Ferreira
6. Aditya Pokharna
7. Witek Kwiatkowski
8. Tetiana Serdiuk
9. Paola Picotti
10. Roland Riek
11. Jason Greenwald

• Curated by eLife

  eLife assessment

  This study presents important findings on the different polymorphs of alpha-synuclein filaments that form at various pH's during in vitro assembly reactions with purified recombinant protein. Of particular note is the discovery of two new polymorphs (1M and 5A) that form in PBS buffer at pH 7. The strength of the evidence presented is convincing. The work will be of interest to biochemists and biophysicists working on protein aggregation and amyloids.

Reviewed by eLife

Direct single-molecule detection and super-resolution imaging with a low-cost portable smartphone-based microscope

1. Morgane Loretan
2. Mariano Barella
3. Nathan Fuchs
4. Samet Kocabey
5. Karol Kołątaj
6. Fernando D. Stefani
7. Guillermo P. Acuna

Reviewed by preLights