Biology subjects

Tueting, C.

Publications and source records attributed to Tueting, C..

12 recordsLinked to original sources

bioRxiv2026

SNPstar: A Web Server Linking Allelic Variation to Protein Structure and Function in Arabidopsis thaliana

Understanding how natural genetic variants affect protein structure and function is central to plant biology. The 1001 Genomes Project has catalogued millions of single nucleotide polymorphisms (SNPs) across more than a thousand Arabidopsis thaliana accessions, offering an unprecedented opportunity to relate sequence variation to three-dimensional protein structure and population context. Yet, realizing it requires tools that integrate these scales in one accessible framework. Here we present SNPstar, a web server that links allelic variation in A. thaliana to AlphaFold3-predicted structures through a gene-centric, interactive interface. SNPstar annotates each variant with descriptive features, thermodynamic stability estimates, protein domain context, and genome-wide association results, and computes haplotypes and proteotypes that group accessions by shared DNA or protein sequence. Researchers can characterize variants, visualize their structural context, map their geographic distribution, and prioritize accessions for experimental validation without local computational infrastructure. We demonstrate SNPstar with two case studies. The first recapitulates known loss-of-function variation in the cadmium transporter HMA3, validating that SNPstar prioritizes functionally consequential alleles. The second uses SNPstar-defined proteotypes to identify an N-terminal SNP combination in ARGONAUTE 2 that distinguishes accessions differing in in vitro siRNA-directed target cleavage, linking protein-coding variation to a measurable molecular phenotype. SNPstar thus helps translate natural variation into mechanistic insight.

plant biology↗

bioRxiv2026

Revisiting p53:Sirt1 interaction in the light of controlling p53 acetylation levels

The NAD+-dependent deacetylase sirtuin 1 (Sirt1) is known to regulate the tumor suppressor p53 via deacetylation, but the structural basis of the protein-protein interaction between full-length p53 and Sirt1 has so far remained elusive. We apply an integrated approach, combining structural mass spectrometry (MS) with data-driven molecular docking, to study the interaction between human p53 and Sirt1. Sirt1 was found to bind exclusively to acetylated p53 forming complexes with a 1:1 stoichiometry, irrespectively of p53s oligomeric state. The lysine residue at position 582 (K582) in p53 was identified as predominant acetylation site showing a selective Sirt1-dependent deacetylation at this position. Cross-linking mass spectrometry (XL-MS) provided valuable distance constraints between p53 and Sirt1. Specifically, cross-links created between p53-K382 / Sirt1-K427 and p53-K120 / Sirt1-K622 give hints on a highly flexible interface. Molecular docking was conducted based on the distance constraints imposed by the cross-links, positioning Sirt1 at the DNA-binding and tetramerization domains of p53. This gives a rationale for a steric exclusion of additional Sirt1 molecules binding to p53. We present the first structural model of the full-length p53:Sirt1 (1:1) complex, establishing a mechanistic framework that links p53 activity to its Sirt1-controlled acetylation status.

biochemistry↗

bioRxiv2025

Structural basis of neurofibromin tetramerization and dimer-tetramer equilibrium

Human neurofibromin (NF1) is a tumor suppressor multidomain protein known to regulate cellular functions as a dimer. Using cryo-EM, we discovered that neurofibromin can form more highly organized structures and describe tetramerization and a dynamic dimer-to-tetramer equilibrium with extensive interlocked interfaces as well as structural flexibility. The new tetramer structure generates and modifies interaction surfaces and controls protein functions such as microtubule recruitment, thereby providing novel insights into cellular functions.

molecular biology↗

bioRxiv2024

IQD2 recruits KLCR1 to the membrane-microtubule nexus to promote cytoskeletal mechano-responsiveness in leaf epidermis pavement cells

Plant cells experience a variety of mechanical stresses from both internal and external sources, including turgor pressure, mechanical strains arising from heterogeneous growth between neighboring cells, and environmental factors like touch from soil, rain, or wind [1,2]. These stresses serve as signals at the cell-, tissue- and organismal level to coordinate plant growth during development and stress responses [3]. In plants, the physical cell wall-plasma membrane-microtubule continuum is proposed to be integral in transducing mechanical signals from the exterior to intracellular components [4-6]. Cortical microtubules (CMTs) rapidly reorient in response to mechanical stress to align with the maximal tensile stress direction [7,8]. Several studies proposed that CMTs themselves may act as stress sensors; the precise mechanisms involved in the regulation of CMTs and the modes of sensing, however, are still not clearly understood. Here, we show that IQD2 and KLCR1 are enriched at CMTs in proximity to the plasma membrane. IQD2, which is a bona fide microtubule-associated protein, promotes microtubule localization of KLCR1. By combining cross-linking mass spectrometry (XL-MS) and computational modeling with structure-function studies, we present first experimental insights into the composition and structure of IQD2-KLCR1 complexes. Further, we demonstrate that the IQD2-KLCR1 module is a positive regulator of microtubule mechano-responses in pavement cells. Collectively, our work identifies the IQD2-KLCR1 module as novel regulator of mechanostress-mediated CMT reorientation and provides a framework for future mechanistic studies aimed at a functional dissection of mechanotransduction at the plasma membrane-CMT interface during growth and plant morphogenesis. HighlightsO_LIIQD2 and KLCR1 localize to the plasma membrane-microtubule nexus C_LIO_LIIQD2 is required for efficient microtubule targeting of KLCR1 in planta C_LIO_LIIQD2 physically interacts with KLCR1 and microtubules C_LIO_LIThe IQD2-KLCR1 module promotes mechano-stress induced microtubule reorganization C_LI

plant biology↗

bioRxiv2022

Structural Assessment of the Full-Length Wild-Type Tumor Suppressor Protein p53 by Mass Spectrometry-Guided Computational Modeling

The tetrameric tumor suppressor p53 represents a great challenge for 3D-structural analysis due to its high degree of intrinsic disorder (ca. 40%). We aim to shed light on the structural and functional roles of p53s C-terminal region in full-length, wild-type human p53 tetramer and their importance for DNA binding. For this, we employed complementary techniques of structural mass spectrometry (MS) in an integrated approach with AI-based computational modeling. Our results show no major conformational differences in p53 between DNA-bound and DNA-free states, but reveal a substantial compaction of p53s C-terminal region. This supports the proposed mechanism of unspecific DNA binding to the C-terminal region of p53 prior to transcription initiation by specific DNA binding to the core domain of p53. The synergies between complementary structural MS techniques and computational modeling as pursued in our integrative approach is envisioned to serve as general strategy for studying intrinsically disordered proteins (IDPs) and intrinsically disordered region (IDRs).

biochemistry↗

bioRxiv2022

AI-guided cryo-EM probes a thermophilic cell-free system with succinyl-coA manufacturing capability

Cell-free systems display tremendous potential for biotechnological applications, complementing in vitro reconstituted enzymatic processes and traditional expression systems. However, they often represent "black boxes" without much insight into their components. Here, we characterize a thermophilic cell-free system that produces succinyl-CoA and discern its intrinsic, non-stochastic organization. By employing biochemical, biophysical, and bioinformatic methods we resolve its molecular composition, 3D architecture and molecular function at atomic resolution. We further report the high-resolution cryo-EM structure of the reactions main component, the oxoglutarate dehydrogenase complex core (E2o), which displays various structural adaptations. These include hydrogen bonding patterns confining interactions of participating enzymes (E1o-E2o-E3), electrostatic tunneling that drives inter-communication between subunits, and the presence of a flexible subunit, the E3BPo connecting E2o and E3. This multi-scale analysis of a cell-free system provides a blueprint for structure-function studies of complex mixtures of biotechnological value.

biochemistry↗

bioRxiv2022

Delineating organizational principles of the endogenous L-A virus by cryo-EM and computational analysis of native cell extracts

The high abundance of most viruses in infected host cells benefits their structural characterization; endogenous viruses are present in low copy numbers, however, and are therefore challenging to investigate. Here, we retrieve cell extracts enriched with an endogenous virus, the yeast L-A virus. The determined cryo-EM structure discloses capsid-stabilizing cation-{pi} stacking and an interplay of non-covalent interactions from ten distinct capsomere interfaces. The capsid-embedded mRNA decapping active site trench is supported by a constricting movement of two opposite-facing loops. tRNA-loaded polysomes and other biomacromolecules, presumably mRNA, are found in virus proximity while stacked dsRNA bundles and the sub-stoichiometric polymerase localize underneath the capsid surface. Mature viruses participate in larger viral communities resembling their rare in-cell equivalents in terms of size, composition, and inter-virus distances. Our results collectively describe a 3D-architecture of a viral milieu, opening the door to cellextract-based high-resolution structural virology.

biochemistry↗

bioRxiv2022

Exotic alleles of EARLY FLOWERING 3 determine plant development and grain yield in barley

EARLY FLOWERING 3 (ELF3) is an important regulator of various physiological and developmental processes and hence may serve to improve plant adaptation which will be substantial for future plant breeding. To expand the limited knowledge on barley ELF3 in determining agronomic traits, we conducted field studies with heterogeneous inbred families (HIFs) derived from selected lines of the wild barley nested association mapping population HEB-25. During two growing seasons, phenotypes of nearly isogenic HIF sister lines, segregating for exotic and cultivated alleles at the ELF3 locus, were compared for ten developmental and yield-related traits. We determine novel exotic ELF3 alleles and show that HIF lines, carrying the exotic ELF3 allele, accelerated plant development compared to the cultivated ELF3 allele, depending on the genetic background. Remarkably, the most extreme phenotypic effects could be attributed to one exotic ELF3 allele, differing in only one SNP from the cultivated Barke ELF3 allele. This SNP causes an amino acid change, which predictively has an impact on the protein structure of ELF3, thereby possibly affecting phase separation behaviour and nano-compartment formation of ELF3 and, potentially, also affecting its local cellular interactions causing significant trait differences between HIF sister lines.

genetics↗

bioRxiv2020

First 3D-Structural Data of Full-length Rod-Outer-Segment Guanylyl Cyclase 1 in Bovine Retina by Cross-linking/Mass Spectrometry

The rod-outer-segment guanylyl cyclase 1 (ROS-GC1) is a key transmembrane protein for retinal phototransduction. Mutations of ROS-GC1 correlate with different retinal diseases that often lead to blindness. No structural data are available for ROS-GC1 so far. We performed a 3D-structural analysis of native ROS-GC1 from bovine retina by cross-linking/mass spectrometry (XL-MS) and computational modeling. Absolute quantification and activity measurements of native ROS-GC1 were performed by MS-based assays directly in bovine retina samples. Our data present the first 3D-structural analysis of active, full-length ROS-GC1 in bovine retina. We propose a novel domain organization for the intracellular domain ROS-GC1. Our XL-MS data reveal that the -helical domain connecting the kinase homology and catalytic domains can acquire different conformations. Also, the XL-MS data of native ROS-GC1 in bovine retina agree with a dimeric architecture. Our integrated approach can serve as a blueprint for conducting 3D-structural studies of membrane proteins in their native environment.

biochemistry↗

bioRxiv2020

Structural Analysis of 70S Ribosomes by Cross-Linking/Mass Spectrometry Reveals Conformational Plasticity

The ribosome is not only a highly complex molecular machine that executes translation according to the central dogma of molecular biology, but also an exceptional specimen for testing and optimizing cross-linking/mass spectrometry (XL-MS) workflows. Due to its high abundance, ribosomal proteins are frequently identified in proteome-wide XL-MS studies of cells or cell extracts. Here, we performed in-depth cross-linking of the E. coli ribosome using the amine-reactive cross-linker diacetyl dibutyric urea (DSAU). We analyzed 143 E. coli ribosomal structures, mapping a total of 10,771 intramolecular distances for 126 cross-link-pairs and 3,405 intermolecular distances for 97 protein pairs. Remarkably, 44% of intermolecular cross-links covered regions that have not been resolved in any high-resolution E. coli ribosome structure and point to a plasticity of cross-linked regions. We systematically characterized all cross-links and discovered flexible regions, conformational changes, and stoichiometric variations in bound ribosomal proteins, and ultimately remodeled 2,057 residues (15,794 atoms) in total. Our working model explains more than 95% of all cross-links, resulting in an optimized E. coli ribosome structure based on the cross-linking data obtained. Our study might serve as benchmark for conducting biochemical experiments on newly modeled protein regions, guided by XL-MS. Data are available via ProteomeXchange with identifier PXD018935.

biochemistry↗

bioRxiv2019

2.7 A cryo-EM structure of vitrified M. musculus H-chain apoferritin from 200 keV \"screening microscope\"

Here we present the structure of mouse H-chain apoferritin at 2.7 [A] (FSC=0.143) solved by single particle cryogenic electron microscopy (cryo-EM) using a 200 kV device. Data were collected using a compact, two-lens illumination system with a constant power objective lens, without the use of energy filters or aberration correctors. Coulomb potential maps reveal clear densities for main chain carbonyl oxygens, residue side chains (including alternative conformations) and bound solvent molecules. We argue that the advantages offered by (a) the high electronic and mechanical stability of the microscope, (b) the high emission stability and low beam energy spread of the high brightness Field Emission Gun (x-FEG), (c) direct electron detection technology and (d) particle-based Contrast Transfer Function (CTF) refinement have contributed to achieving resolution close to the Rayleigh limit. Overall, we show that basic electron optical settings for automated cryo-electron microscopy imaging, widely thought of as a "screening cryo-microscope", can be used to determine structures approaching atomic resolution. HighlightsO_LIThe 2.7 [A] structure of mouse apoferritin was solved using a 200 keV screening cryo-microscope C_LIO_LIThe apoferritin reconstruction was resolved without an energy filter, aberration correctors, or constant-power condenser lenses C_LIO_LIComparison to available crystallographic and cryo-EM structures from high-end cryo-microscopes demonstrates consistency in resolved water molecules, metals and side chain orientations C_LIO_LIAlthough radiation damage is more prominent at 200 keV compared to 300 keV, this type of instrumentation is more accessible to research laboratories due to its compactness and simplicity C_LI

biophysics↗

bioRxiv2018

Reconstitution of mammalian Cleavage Factor II involved in 3’ processing of mRNA precursors

Cleavage factor II (CF II) is a poorly characterized component of the multi-protein complex catalyzing 3 cleavage and polyadenylation of mammalian mRNA precursors. We have reconstituted CF II as a heterodimer of hPcf11 and hClp1. The heterodimer is active in partially reconstituted cleavage reactions, whereas hClp1 by itself is not. Pcf11 moderately stimulates the RNA 5 kinase activity of hClp1; the kinase activity is dispensable for RNA cleavage. CF II binds RNA with nanomolar affinity. Binding is mediated mostly by the two zinc fingers in the C-terminal region of hPcf11. RNA is bound without pronounced sequence-specificity, but extended G-rich sequences appear to be preferred. We discuss the possibility that CF II contributes to the recognition of cleavage/polyadenylation substrates through interaction with G-rich far-downstream sequence elements.

biochemistry↗