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of the Heinrich-Heine-Universität
Communities
- Heinrich Heine University cooperates with numerous research institutions and networks beyond the boundaries of the faculties. The HHU's affiliated institutes in particular act as a link to industry. As independent institutions, they maintain close contact with research in the faculties and participate in the training of young academics.
- One of our foci today, linking all faculties, are the Life Sciences. Cross-departmental, joint study programmes (such as Business Chemistry) are one of our major strengths.
- The ZIM is a central operating unit of the Heinrich Heine University. It is a service and competence center for all aspects of digital information supply and processing, digital communication and the use of digital media.
Recent Submissions
Data for "Mechanistic Insights into the Structural Asymmetry of the LanFEG Transporter NisFEG in Lantibiotic Immunity"
(2025) Cea, Pablo; Gohlke, Holger
Nisin is one of the best studied antimicrobial peptides. Still, how nisin-producing strains can protect themselves against nisin’s bactericidal effects is only partially understood. Located within the nisin biosynthesis operon, the heterotetrameric ABC transporter NisFEG transports nisin to the extracellular environment, granting autoimmunity to the producer strain. NisFEG belongs to the LanFEG family of ABC transporters, members of which are found in some lantibiotic-producing bacterial strains. However, their structure has not been elucidated. In this work, we constructed a full atom model of NisFEG in the ATP-bound conformation. The architecture of the complex reveals a narrow transmembrane interface with prominent lateral clefts, similar to those observed in other exporters of hydrophobic compounds. Through molecular dynamics (MD) simulations, we observed that one of the most conserved elements of the LanFEG family, the E-loop of the nucleotide binding domain, interacts preferentially with a small intracellular helix of the NisG transmembrane chain. Cosolvent MD simulations reveal the presence of a putative binding site within the lateral cleft of the transporter, next to the transmembrane chain NisE. Mutational analysis showed that large hydrophobic residues near this putative site are relevant to the transporter function, and more so than analogous residues in the opposite cleft. Our results suggest that nisin extrusion operates in an asymmetric manner, where contacts between the E-loop and NisG are the driving force for the conformational changes triggered by ATP hydrolysis, whereas the NisE subunit is the main mediator of interactions with the lantibiotic. This functional asymmetry could provide an explanation for why the LanFEG family has evolved two distinct transmembrane chains, where each one was selected to perform a single step in an optimal way, maximizing the immunity of lantibiotic-producing bacteria.
Data for "Early-stage autophagy inhibitors targeting the ATG101-ATG13 subunit of the ULK1 complex"
(2025) Mudrovcic, Korana; Gopalswamy, Mohanraj; Gohlke, Holger
Autophagy is commonly up- or down-regulated in cancer cells due to the unique metabolic needs of these cells, and small molecules modulating the autophagy pathway are already in clinical trials. However, specific autophagy-targeting compounds remain rare. A new potential mechanism for effective early-stage autophagy inhibition was described by us and others recently, involving the inhibition of the interaction between ATG101 and ATG13 subunits of the autophagy-initiating ULK1 complex. Here, we describe the discovery of two small molecules inhibiting the ATG101-ATG13 interaction, one by binding to ATG101 with micromolar affinity (EC50 = 151 µM) and the other by binding to both ATG101 and ATG13 with micromolar affinity (EC50 = 135 µM and EC50 = 107 µM, respectively). In two independent assays, both compounds inhibit autophagy. Scrutinizing the binding mechanism by molecular dynamics simulations and STD-NMR spectroscopy indicates that the compounds bind to ATG101 in an orthosteric fashion, at the interface of the protein-protein interaction, while the binding to ATG13 is allosteric. Both compounds have a favorable predicted ADME-Tox profile. The compounds can serve as tool compounds to inhibit autophagy or as candidates for further optimization toward lead structures.
Data for "Identification of autophagy inhibitors selectively targeting the ATG13-ATG101 protein-protein interaction"
(2025) Mudrovcic, Korana; Gopalswamy, Mohanraj; Gohlke, Holger
The dysregulation of autophagy promotes the development of several diseases like such as neurodegeneration, infection, or cancer. To keep up with their metabolic demand under low nutrient and/or oxygen conditions typically present in the tumor microenvironment, cancer cells can upregulate autophagy autonomously or in surrounding cells. Therefore, the inhibition of autophagy is desired in these settings. However, to date, drugs targeting autophagy selectively remain rare. The autophagy-inducing ULK1 complex comprises ULK1/2, FIP200, and a heterodimer consisting of ATG13 and ATG101. We previously showed that the ATG13-ATG101 protein-protein interaction is crucial for the assembly of the ULK1 complex and initiation of autophagic activity. Thus, targeting the ATG13-ATG101 protein-protein interaction with small molecules promises to yield new tools for the study of autophagy as well as to deliver new therapeutic starting points. By screening a diversity set of 15k compounds in a biochemical setup, followed by extensive cell-based validation studies, we identified the compounds AFS30 and AFS32. Both compounds inhibited the ATG13-ATG101 PPI in the low micromolar range and led to reduced autophagic activity in different cell lines, with IC50 values of 3-4 µM in the LC3 HiBiT reporter assay. Spectral shift assays, molecular dynamics simulations, and STD-NMR suggested that the compounds bind allosterically to ATG13. AFS30 and AFS32 also promoted apoptosis in different cancer cell lines exposed to nutrient stress. We propose that AFS30 and AFS32 are promising lead compounds for the development of PPI inhibitors that selectively inhibiting the ATG13-ATG101 interaction and thus autophagy.
Data for "Sulfated glycosaminoglycans inhibit Arenavirus entry and modulate anti-viral immunity and pathology"
(N/A, 2025) Rähse, Nick; Lapsien, Marco; Gohlke, Holger
Viral infections pose significant challenge due to limited availability and efficacy of treatments. Current therapies primarily inhibit viral replication, but are often virus-specific and may lead to drug resistance. Sulfated glycosaminoglycans (GAGs) emerged as promising candidates for antiviral therapy, preventing viral binding to host cells and inhibiting cell entry, offering a novel therapeutic strategy targeting broad range of viruses, addressing the limitations of existing antiviral drugs. Here, we demonstrate highly-sulfated GAGs are able to limit infectivity of different pathogenic and non-pathogenic Arenaviruses. In an in vivo model setting, dextran sulfate administered during the acute phase of LCMV infection reduced viral load in organs and decreased liver pathology, which was associated with improved effector T cell functions. In turn, exposure of LCMV towards dextran sulfate at the beginning of infection caused limited immune activation, resulting in reduced T cell immunity, prolonged infection and increased immunopathology. These findings indicate the potential use of GAGs against Arenavirus infections and highlight that timing of therapeutic regimens might be critical for clinical efficacy.
Data for "Evidence for Epibatidine Binding to the Desensitization Gate in α7 nAChR from Molecular Dynamics Simulations and Cryo-EM"
(N/A, 2025) Kaiser, Jesko; Gertzen, Christoph; Mann, Daniel; Sachse, Carsten; Gohlke, Holger
The homopentameric α7 nicotinic acetylcholine receptor (nAChR) is a ligand-gated ion channel widely expressed in the human nervous system and susceptible to regulation via allosteric modulators. A recent cryo-EM map of the receptor (EMD 22983) in the presence of (±)-epibatidine revealed the presence of several Coulomb density regions that did not contain an atomic model (PDB ID: 7KOX). We conducted unbiased molecular dynamics simulations of free ligand diffusion of the components of experimental buffers utilized to obtain the cryo-EM structure in the presence of α7-nAChR. In addition to the previously documented binding of epibatidine to the orthosteric site and Ca2+ between E44 and E172, the simulations indicated that epibatidine can also bind within the pore of α7-nAChR. This finding is consistent with the unmodeled Coulomb density observed in the region of the desensitization gate. The data presented here suggests that nAChR ligands characterized as orthosteric binders may bind to additional sites within the receptor and expands the receptor’s pocketome.
Data for "Molecular Insights into CLD Domain Dynamics and Toxin Recruitment of the HlyA E. coli T1SS"
(N/A, 2025) Gentile, Rocco; Schott-Verdugo, Stephan; Khosa, Sakshi; Bonus, Michele; Reiners, Jens; Smits, Sander H.J.; Schmitt, Lutz; Gohlke, Holger
Escherichia coli is a Gram-negative opportunistic pathogen causing nosocomial infections through the production of various virulence factors. Type 1 secretion systems (T1SS) contribute to virulence by mediating one-step secretion of unfolded substrates directly into the extracellular space, bypassing the periplasm. A well-studied example is the hemolysin A (HlyA) system, which secretes the HlyA toxin in an unfolded state across the inner and outer membranes. T1SS typically comprise a homodimeric ABC transporter (HlyB), a membrane fusion protein (HlyD), and the outer membrane protein TolC. Some ABC transporters in T1SS also contain N-terminal C39 peptidase or peptidase-like (CLD) domains implicated in substrate interaction. Recent cryo-EM studies have resolved the inner-membrane complex as a trimer of HlyB homodimers with associated HlyD protomers. However, a full structural model including TolC remains unavailable. We present the first complete structural model of the HlyA T1SS, constructed using template- and MSA-based information and validated by SAXS. Molecular dynamics simulations provide insights into the function of the CLD domains, which are partially absent from existing cryo-EM structures. These domains may modulate transport by stabilizing specific conformations of the complex. Simulations with a C-terminal fragment of HlyA indicate that toxin binding occurs in the occluded conformation of HlyB, potentially initiating substrate transport through a single HlyB protomer before transitioning to an inward-facing state. HlyA binding also induces allosteric effects on HlyD, altering key residues involved in TolC recruitment. These results indicate how substrate recognition and transport are coupled and may support the development of antimicrobial strategies targeting the T1SS.