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Peptides are desirable therapeutics due to their inherent potency, safety, and ability to engage complex protein surfaces. Slower kinetics of protein-peptide (un)binding can directly influence their drug efficacy and duration of action, in part by improving plasma stability of the peptide. A better understanding of peptide binding mechanisms would benefit for the development of next-generation peptide-based drugs with optimized kinetic properties. The calcitonin receptor-like receptor:receptor activity-modifying proteins 1 (CLR:RAMP1) complex and its endogenous agonist peptide calcitonin gene-related peptide (CGRP) are of particular interest due to their central role in migraine pathophysiology.

Channelrhodopsins (ChRs) are light-controlled ion channels that have become indispensable tools in the field of optogenetics. Channelrhodopsin-1 from Chlamydomonas augustae (CaChR1) is a phylogenetically early member of this class of proteins with red-shifted absorption and pronounced photocurrent kinetics, but the exact correlation between its photocycle intermediate states and channel conductivity remains to be elucidated. Here, we use time-resolved optical absorption spectroscopy (TROD) in the nanosecond to second range for wild-type (WT) CaChR1 and its E169Q and D299N counterion variants.

The fusion pore is an important focus of research in exocytosis. It tracks the onset and progress of secretion from a vesicle, and its structure has important implications for the mechanism of membrane fusion. Fusion pores can be visualized with structural methods, and the diameter can be estimated by various physiological techniques that measure flux. Estimates of fusion pore size vary widely and the divergent results have been a source of confusion. This Perspective assesses the different approaches to determining the diameter of a fusion pore.

RNA recognition by proteins is governed not only by static structure but also by allostery encoded within non-local dynamic motifs. In this study, we systematically identify allosteric communication hubs in RNA and map multiple residue-connected pathways, revealing how these networks are rewired upon mutation and protein binding. To capture these effects under physiological salt conditions, we performed extensive atomistic simulations of TAR RNA, both in its apo and Tat-protein bound states, across three immunodeficiency virus variants, BIV, HIV-1, and HIV-2.

Beta-barrel structures are critical components of bacterial outer membranes, where they facilitate transport, cell signaling, antibiotic resistance, and structural integrity. A key feature of beta-barrels is their strand count, which influences pore diameter, binding site locations, and functional properties. However, because of breaks in strands and the presence of strands in periplasmic domains and plug domains, manual counting is inefficient and current algorithms do not accurately determine barrel strand count.

Disordered protein linkers are essential for multidomain protein function and engineering, but quantitative methods for their biophysical characterization remain limited. We combined NMR experiments with molecular dynamics simulations to demonstrate that protein backbone 15N spin relaxation times correlates with backbone rigidities in short disordered linkers. Using a tailored version of the Quality Evaluation Based Simulation Selection (QEBSS) framework, we characterized four model peptides: (GGS)3, (GPS)3, K(AP)5K, and KKEEVKKEEV-(PK)7KEEVKKEEVKK, representing common natural and engineered linker repeats.

Thecollective dynamics of subcellular biological processes is often difficult to assess experimentally, due to the challenges associated with spatial and temporal resolution, labelling or multiple scattering. X-ray photon correlation spectroscopy (XPCS) is in principle well suited to probe collective dynamics by quantifying dispersion relations in complex fluids in general, and biomolecular systems in particular. However, the low scattering signal and the sensitivity to radiation damage set stringent limits to many applications.

Kinesin-5 motors are bipolar tetramers that crosslink and slide antiparallel microtubules during mitotic spindle assembly. Fungal kinesin-5 motors, such as Cin8, exhibit bidirectional motility, switching between minus- and plus-end-directed stepping in response to environmental conditions; however, the molecular basis of this directional switching remains unclear. To better understand the origin of this bidirectional behavior, we investigated the motility and ATPase kinetics of two Cin8 dimers, created by fusing the motor domains to a stable coiled-coil domain from kinesin-1.

Heterotrimeric protein complexes are central regulators of intracellular signalling, yet their dynamic assembly and transport in living cells remain difficult to resolve. Here we present spatial triple-correlation spectroscopy (S3CS), a fluorescence fluctuation method that integrates three-channel line-scan microscopy with a spatial triple-correlation function to directly detect fluorescent heterotrimers and map their movement relative to subcellular architecture. Simulations establish that S3CS quantitatively captures heterotrimer formation, local diffusion, and long-range transport, while live-cell experiments confirm its specificity for following fluorescent ternary assemblies in the presence of free independent subunits.

Animal morphogenesis involves complex tissue deformation processes, which require tight control over tissue rheology. Yet, it remains insufficiently understood how tissue rheology results from the interplay between cellular packing and forces, such as cortical tension or cell-cell adhesion. We follow a biomimetic approach to study this interplay, using oil droplets with tunable adhesion strength to mimic adhesive cells. We expose emulsions to cyclic shear and use a geometric method to quantify their rheology using only imaging data.

Conduction velocity along axons reflects geometric and biophysical influences whose joint statistical organization remains largely uncharacterized. Using high-resolution time-of-arrival measurements along hundreds of identified axonal branches in vitro, we quantified how propagation speed changes along trajectories. The ratio between terminal and initial velocities, ρ=vend/vstart, follows a right-skewed distribution whose shape remains invariant across branch lengths, positions within neurons, and hierarchical aggregation levels.

The antagonistic interaction between small RNAs (sRNAs) and messenger RNAs (mRNAs) constitutes a fundamental regulatory mechanism of gene expression in both prokaryotic and eukaryotic cells. However, the stochastic nature of transcription renders mean-field approximations inadequate for quantitative analysis of such systems. In the regime of strong sRNA-mRNA antagonism, we generalize the conventional probability-generating-function (PGF) framework and derive a novel approximate solution in the form of a generalized PGF, which can be analytically transformed into the time-dependent joint distribution of sRNA and mRNA via Laurent series expansion.