Research Area B - Publications 2015
Nucl. Acids Res., doi: 10.1093/nar/gkv1517
Nucl. Acids Res., online article
During protein synthesis, ribosomes become stalled on polyproline-containing sequences, unless they are rescued in archaea and eukaryotes by the initiation factor 5A (a/eIF-5A) and in bacteria by the homologous protein EF-P. While a structure of EF-P bound to the 70S ribosome exists, structural insight into eIF-5A on the 80S ribosome has been lacking. Here we ...
eLife, 4:e10859. DOI: 10.7554/eLife.10859
eLife, online article
The cytosolic antiviral innate immune sensor RIG-I distinguishes 5′ tri- or diphosphate containing viral double-stranded (ds) RNA from self-RNA by an incompletely understood mechanism that involves ATP hydrolysis by RIG-I's RNA translocase domain. Recently discovered mutations in ATPase motifs can lead to the multi-system disorder Singleton-Merten Syndrome (SMS) ...
The activity of protein phosphatase 5 towards native clients is modulated by the middle- and C-terminal domains of Hsp9
Scientific Reports 5, Article number: 17058, doi:10.1038/srep17058
Protein phosphatase 5 is involved in the regulation of kinases and transcription factors. The dephosphorylation activity is modulated by the molecular chaperone Hsp90, which binds to the TPR-domain of protein phosphatase 5. This interaction is dependent on the C-terminal MEEVD motif of Hsp90. We show that C-terminal Hsp90 fragments differ in their regulation of ...
Selective Inhibition of the Immunoproteasome by Structure-Based Targeting of a Non-catalytic Cysteine
Angew. Chem. Int. Ed., 54, 15888 –15891, DOI: 10.1002/anie.201506631
Clinically applied proteasome inhibitors induce cell death by concomitant blockage of constitutive and immunoproteasomes. In contrast, selective immunoproteasome inhibition is less cytotoxic and has the potential to modulate chronic inflammation and autoimmune diseases. In this study, we rationally designed decarboxylated peptides that covalently target a ...
Reversible Inhibitors Arrest ClpP in a Defined Conformational State that Can Be Revoked by ClpX Association
Angew. Chem. Int. Ed., Volume 54, Issue 52, Pages 15892–15896 , DOI: 10.1002/anie.201507266
Caseinolytic protease P (ClpP) is an important regulator of Staphylococcus aureus pathogenesis. A high-throughput screening for inhibitors of ClpP peptidase activity led to the identification of the first non-covalent binder for this enzyme class. Co-crystallization of the small molecule with S. aureus ClpP revealed a novel binding mode: Because of the rotation ...
Structure of the Dioxygenase AsqJ: Mechanistic Insights into a One-Pot Multistep Quinolone Antibiotic Biosynthesis
Angew. Chem. Int. Ed., 55, 422 –426, DOI: 10.1002/anie.201507835
Multienzymatic cascades are responsible for the biosynthesis of natural products and represent a source of inspiration for synthetic chemists. The FeII/α-ketoglutarate-dependent dioxygenase AsqJ from Aspergillus nidulans is outstanding because it stereoselectively catalyzes both a ferryl-induced desaturation reaction and epoxidation on a benzodiazepinedione. ...
Journal of Molecular Biology, Volume 427, Issue 22, Pages 3572–3586, doi:10.1016/j.jmb.2015.09.012
The association of light chains (LCs) and heavy chains is the basis for functional antibodies that are essential for adaptive immune responses. However, in some cases, LCs and especially fragments consisting of the LC variable (VL) domain are pathologically deposited in fatal aggregation diseases. The two domains of the LC are connected by a highly conserved ...
Hsp90·Cdc37 Complexes with Protein Kinases Form Cooperatively with Multiple Distinct Interaction Sites
THE JOURNAL OF BIOLOGICAL CHEMISTRY, VOL. 290, NO. 52, pp. 30843–30854, doi: 10.1074/jbc.M115.693150
Protein kinases are the most prominent group of heat shock protein 90 (Hsp90) clients and are recruited to the molecular chaperone by the kinase-specific cochaperone cell division cycle 37 (Cdc37). The interaction between Hsp90 and nematode Cdc37 is mediated by binding of the Hsp90 middle domain to an N-terminal region of Caenorhabditis elegans Cdc37 (CeCdc37). ...
The EMBO Journal, Volume 34, Issue 22, pages 2840–2861, DOI: 10.15252/embj.201591593
Mutations in the PTEN-induced kinase 1 (PINK1) are causative of autosomal recessive Parkinson's disease (PD). We have previously reported that PINK1 is activated by mitochondrial depolarisation and phosphorylates serine 65 (Ser65) of the ubiquitin ligase Parkin and ubiquitin to stimulate Parkin E3 ligase activity. Here, we have employed quantitative ...
Targeted Delivery of Proteasome Inhibitors to Somatostatin-Receptor-Expressing Cancer Cells by Octreotide Conjugation
ChemMedChem, Volume 10, Issue 12, pages 1969–1973, DOI: 10.1002/cmdc.201500449
Clinical application of proteasome inhibitors (PIs) is so far limited to peripheral blood cancers due to the pronounced cytotoxicity towards all cell types. Targeted delivery of PIs could permit the treatment of other cancers along with decreasing side effects. Herein we describe the first small-molecule proteasome inhibitor conjugate for targeted delivery, ...
Nature Structural & Molecular Biology, 22, 898–905, doi:10.1038/nsmb.3108
Nature Structural & Molecular Biology, online article
Small heat-shock proteins, including αB-crystallin (αB), play an important part in protein homeostasis, because their ATP-independent chaperone activity inhibits uncontrolled protein aggregation. Mechanistic details of human αB, particularly in its client-bound state, have been elusive so far, owing to the high molecular weight and the heterogeneity of these ...
In vitro analyses of mitochondrial ATP/phosphate carriers from Arabidopsis thaliana revealed unexpected Ca2+-effects
BMC Plant Biology, 15:238, doi:10.1186/s12870-015-0616-0
Background: Adenine nucleotide/phosphate carriers (APCs) from mammals and yeast are commonly known to adapt the mitochondrial adenine nucleotide pool in accordance to cellular demands. They catalyze adenine nucleotide - particularly ATP-Mg - and phosphate exchange and their activity is regulated by calcium. Our current knowledge about corresponding proteins from ...
Nature Structural & Molecular Biology, 22, 767–773, doi:10.1038/nsmb.3086
The signal recognition particle (SRP) recognizes signal sequences of nascent polypeptides and targets ribosome–nascent chain complexes to membrane translocation sites. In eukaryotes, translating ribosomes are slowed down by the Alu domain of SRP to allow efficient targeting. In prokaryotes, however, little is known about the structure and function of Alu ...
Nature Communications, online article
GTPases act as key regulators of many cellular processes by switching between active (GTP-bound) and inactive (GDP-bound) states. In many cases, understanding their mode of action has been aided by artificially stabilizing one of these states either by designing mutant proteins or by complexation with non-hydrolysable GTP analogues. Because of inherent ...
Beilstein J. Org. Chem., 11, 1129–1135, doi:10.3762/bjoc.11.127
Aryl sulfonamides are a widely used drug class for the inhibition of carbonic anhydrases. In the context of our program of photochromic pharmacophores we were interested in the exploration of azobenzene-containing sulfonamides to block the catalytic activity of human carbonic anhydrase II (hCAII). Herein, we report the synthesis and in vitro evaluation of a small ...
PLOS Genetics, DOI:10.1371/journal.pgen.1005188
The life span of non-renewing organisms is determined by the potential of their individual cells to maintain their functions while aging. Nematodes, like Caenorhabditis elegans with their 20 days of adult life, have proven to be excellent model systems to study organismal lifespan, its variability, and its regulation.
Angewandte Chemie, online article
We present a new protein labeling method based on the covalent enzymatic phosphocholination of a specific octapeptide amino acid sequence in intact proteins. The bacterial enzyme AnkX from Legionella pneumophila has been established to transfer functional phosphocholine moieties from synthetically produced CDP-choline derivatives to N-termini, C-termini, and ...
The extreme Albino3 (Alb3) C terminus is required for Alb3 stability and function in Arabidopsis thaliana
Planta, Volume 242, Issue 3, pp 733–746, DOI 10.1007/s00425-015-2352-y
Planta, online article
Main conclusion The extreme Alb3 C terminus is important for Alb3 stability in a light dependent manner, but is dispensable for LHCP insertion or D1 synthesis.
Atomic-Resolution Structures of Discrete Stages on the Reaction Coordinate of the [Fe4S4] Enzyme IspG (GcpE)
Journal of Molecular Biology, online article
IspG is the penultimate enzyme in non-mevalonate biosynthesis of the universal terpene building blocks isopentenyl diphosphate and dimethylallyl diphosphate. Its mechanism of action has been the subject of numerous studies but remained unresolved due to difficulties in identifying distinct reaction intermediates. Using a moderate reducing agent and an epoxide ...
The Chaperone Activity of the Developmental Small Heat Shock Protein Sip1 Is Regulated by pHDependent Conformational Changes
Molecular Cell, online article
Small heat shock proteins (sHsps) are ubiquitous molecular chaperones that prevent the aggregation of unfolding proteins during proteotoxic stress. In Caenorhabditis elegans, Sip1 is the only sHsp exclusively expressed in oocytes and embryos. Here, we demonstrate that Sip1 is essential for heat shock survival of reproducing adults and embryos. X-ray ...
PNAS, online article
Hsp90 is a molecular chaperone involved in the activation of numerous client proteins, including many kinases. The most stringent kinase client is the oncogenic kinase v-Src. To elucidate how Hsp90 chaperones kinases, we reconstituted v-Src kinase chaperoning in vitro and show that its activation is ATP-dependent, with the cochaperone Cdc37 increasing the ...
Macyranones: Structure, Biosynthesis, and Binding Mode of an Unprecedented Epoxyketone that Targets the 20S Proteasome
JACS, online article
In our screening efforts to identify unique scaffolds from myxobacteria for the drug discovery process, we used LC-SPE-NMR-MS techniques to isolate six linear peptides, termed macyranone A–F, from Cystobacter fuscus MCy9118. The macyranones are characterized by a rare 2-methylmalonamide moiety and an α-amino ketone fragment including an α′,β′-epoxyketone in ...