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Hoeweler, U.

Publications and source records attributed to Hoeweler, U..

2 recordsLinked to original sources

kontakteUR: transforming coordinates to chemical intuition to focus on essential interactions in biomolecular systems

Molecular interactions govern cellular function, making them essential to discover biomolecular mechanisms by unravelling structure-function relationships. The rapid growth of AI-based prediction, experimental determination, and molecular dynamics simulations generates structural data at an unprecedented scale. However, structural information is typically represented as Cartesian coordinates, leaving chemical interactions and conformational relationships largely implicit. We introduce a high-throughput framework transforming structural geometry into a standardized, compact contact space. Moving beyond simple distance cutoffs, it provides a chemically and geometrically informed representation of various residue-residue interactions, their temporal changes, and conformations at residue-level resolution. Our contact-space representation enables systematic comparison and classification even for large-scale analysis. Case studies spanning structure comparison or studies of protein-protein, protein-ligand, protein-RNA, and antibody-antigen complexes, demonstrate how contact-space analysis reveals interaction patterns, identifies key mutation sites, and links structural features to experimental observations. With these and further applications, kontakteUR elucidates biomolecular function and assists targeted protein design, with results suited for further processing by artificial intelligence algorithms.

biochemistry↗

A fast and accurate calculation method for light induced isomerization of retinal proteins in real time

Retinal is a chromophore covalently bound to various photoreceptors. Its photo-induced isomerization triggers a series of structural changes named photocycle, leading to diverse biological functions. Despite tremendous advances in structural biology and artificial intelligence-driven structure prediction, it remains challenging to analyze all photocyclic intermediates. Here, we present an optimized computational approach to calculate RSBH+ isomerization and its induced structural changes based on a classical molecular mechanics approach using quantum mechanically improved retinal force field parameters. Isomerization is induced by an excited state restraint which is subsequently relaxed to allow the return to the electronic ground state. We applied this approach to the key protein of optogenetics, Channelrhodopsin-2 from Chlamydomonas reinhardtii (CrChR2). Besides the reformation of the alltrans/CN-anti ground state, we observed the production of a mixture of two isomeric states 13-cis/CN- anti and 13-cis/CN-syn. These findings agree with the previously found branched photocycle model based on experimental data. Our calculations show an asymmetric potential energy landscape of the excited state leading to a corresponding isomerization state distribution. Unlike earlier publications, our procedure describes the retinal photoisomerization on the natural timescale of 500 fs. As our newly derived retinal force field parameter set precisely relies on quantum biological knowledge, it assists to improve the refinement of experimental structure biological data. Our readily customizable strategy provides mechanistic insights at high spatio-temporal resolution, which permits accurate structural predictions of early photocycle intermediates. These insights will stimulate the rational design of optogenetic tools thus providing improved diagnostic and therapeutic approaches for neuronal and other diseases. HighlightsO_LIuniversal method to study molecular mechanism of optogenetic tools C_LIO_LIretinal photo-isomerization calculation in real time C_LIO_LIprediction of branched photo cycle agrees with experimental IR spectroscopic results C_LIO_LIdetected asymmetric excited state potential energy landscape C_LIO_LIassists to improve structural model refinement of retinal proteins C_LI Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=116 HEIGHT=200 SRC="FIGDIR/small/707937v1_ufig1.gif" ALT="Figure 1"> View larger version (28K): org.highwire.dtl.DTLVardef@71f7fdorg.highwire.dtl.DTLVardef@503482org.highwire.dtl.DTLVardef@1a77120org.highwire.dtl.DTLVardef@1f410a0_HPS_FORMAT_FIGEXP M_FIG C_FIG

biophysics↗