Biophysics

eLife assessment

This important study analyzes in an original way how tension pattern dynamics can reveal the contribution of active versus passive intercalation during tissue elongation. The authors develop a compelling, elegant analytical framework (isogonal tension decomposition) to disentangle the passive (adjacent tissues pulling) and active (local tension anisotropy) contributions to intercalation events. This allows the generation of global maps of tissue mechanics that will be extremely helpful in the field of biomechanics.

eLife assessment

This important study presents the structure of human heparan-alpha-glucosaminide N-acetyltransferase (HGSNAT) in the acetyl-CoA bound state, providing the first description of the architecture of this family of integral membrane enzymes, and revealing the mode of acetyl-CoA binding. The structural work is convincing, with a high resolution and isotropic single-particle cryoEM map and an atomic model that is well-justified by the density map, with strong density for the acetyl-CoA ligand. However, experimental support for the molecular mechanism of the HS acetylation reaction and the impact of disease-causing mutations is incomplete. This work will be of interest to biochemists and structural biologists studying the structure and function of integral membrane enzymes, as well as those interested in genetic diseases resulting from mutations in this family of enzymes, such as mucopolysaccharidosis IIIC (MPS III-C).

eLife assessment

In this valuable contribution, the authors present a novel and versatile probabilistic tool for classifying tracking behaviors and understanding parameters for different types of single-particle motion. The tool will be broadly applicable to single-particle tracking studies. While some reviewers feel that the methodology has been convincingly tested by computational comparisons and experimental data, others feel that the mathematical foundation needs to be strengthened and clearly defined.

eLife assessment

A combination of molecular dynamics simulation and state-of-the-art statistical post-processing techniques provided valuable insight into GPCR-ligand dynamics. This manuscript provides solid evidence for differences in the binding/unbinding of classical cannabinoid drugs from new psychoactive substances. The results could aid in mitigating the public health threat these drugs pose.

eLife assessment

This work presents fundamental new insights into the conductivity of freshwater cable bacteria. The evidence supporting the conclusions, which was collected using appropriate techniques, is compelling. The work will be of interest to environmental microbiologists and the microbial electrochemistry community.

eLife assessment

This valuable paper investigates how fish avoid thermal disturbances that occur on fast timescales. The authors use a creative experimental approach that quickly creates a vertical thermal interface, which they combine with careful behavioral analyses. The evidence supporting their results is solid, but there is a potential confounding factor between temperature and vertical positioning, and characterization of the thermal interface would greatly assist in interpreting the results.

eLife assessment

The authors performed extensive coarse-grained molecular dynamics simulations of 140 different prion-like domain variants to interrogate how specific amino acid substitutions determine the driving forces for phase separation. The analyses are solid, and the predictive scaling laws can aid in identifying potential phase-separating regions in uncharacterized proteins. Overall, this is a valuable contribution to the field of biomolecular condensates. It exemplifies how data-driven methodologies can uncover new insights into complex biological phenomena.

eLife assessment

This useful study uses fluorescence lifetime imaging (FLIM) and tmFRET to resolve resting vs. active conformational heterogeneity and free energy differences driven by cGMP and cAMP in a tetrameric arrangement of isolated CNBDs from a prokaryotic CNG channel. The data are compelling and the experimental approach features rigorous new methods and analyses. Limitations include (1) only the cytosolic fragments of the channel were studied; (2) the results are not adequately discussed in the context of the extensive prior literature about conformational dynamics and energetics of CNBD-containing ion channels; (3) ambiguity in the stoichiometry of labeled:unlabeled subunits; and (4) the lack of a discussion of alternative interpretations of the data. The study will be of interest to scientists working on the structural mechanisms of membrane proteins.

eLife assessment

This study provides useful insights into the conformational dynamics of the nucleic acid recognition lobe of GeoCas9, a thermophilic Cas9 from Geobacillus stearothermophilus. The influence of local dynamics and allosteric regulation on guide RNA binding affinity and DNA cleavage specificity is investigated via cutting-edge NMR approaches and mutagenesis. While backed by rigorous biophysical analyses, evidence supporting the proposed mechanistic model is found to be incomplete due to the limited impact of the studied mutations on GeoCas9 cleavage activity. This work will be of interest to biochemists and biophysicists interested in interdomain communication and allosteric mechanisms in Cas9 enzymes.

Evaluation Summary:

The authors combined atomistic simulations and continuum mechanics models to probe how structural features of the M2 channel impact the local membrane properties and stability of the channel in membranes of different curvatures. The insights gained in this work can potentially lead to novel strategies that screen for drug molecules that stabilize fission-incompetent conformations of the M2 channel. The multi-scale computational approach will find utility to many problems in membrane reshaping.

(This preprint has been reviewed by eLife. We include the public reviews from the reviewers here; the authors also receive private feedback with suggested changes to the manuscript. Reviewer #2 and Reviewer #3 agreed to share their name with the authors.)