TY - JOUR A1 - Müller, T. A1 - Dieckmann, T. A1 - Sebald, Walter A1 - Oschkinat, H. T1 - Aspects of receptor binding and signalling of interleukin-4 investigated by site-directed mutagenesis and NMR spectroscopy N2 - Cytokines are hormones that carry information from ceJI to ceH. This information is read from their surface upon binding to transmembrane receptors and by the subsequent initiation of receptor oligomerization. An inftuence on this process through mutagenesis on the hormone surface is highly desirab)e for medical reasons. However, an understanding of hormone-receptor interactions requires insight into the structural changes introduced by the mutations. In this line structural studies on human TL-4 and the medically important IL-4 antagonists YI24D and Y124G are presented. The site a.round YI24 is an important epitope responsible for the a.bility of 11-4 t.o ca.use a signal in the target cells. It is shown that the local main-chain structure around residue 124 in the variants remains unchanged. A strategy is presented here which allows the study of these types of proteins and their variants by NMR which does not require carbon Iabeiied sa.mples. KW - Biochemie KW - Interleukin-4 KW - protein structure KW - NMR KW - signal transduction Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-62444 ER - TY - JOUR A1 - Schmitt, Dominik R. A1 - Kuper, Jochen A1 - Elias, Agnes A1 - Kisker, Caroline T1 - The Structure of the TFIIH p34 Subunit Reveals a Von Willebrand Factor A Like Fold JF - PLoS ONE N2 - RNA polymerase II dependent transcription and nucleotide excision repair are mediated by a multifaceted interplay of subunits within the general transcription factor II H (TFIIH). A better understanding of the molecular structure of TFIIH is the key to unravel the mechanism of action of this versatile protein complex within these vital cellular processes. The importance of this complex becomes further evident in the context of severe diseases like xeroderma pigmentosum, Cockayne's syndrome and trichothiodystrophy, that arise from single point mutations in TFIIH subunits. Here we describe the structure of the p34 subunit of the TFIIH complex from the eukaryotic thermophilic fungus Chaetomium thermophilum. The structure revealed that p34 contains a von Willebrand Factor A (vWA) like domain, a fold which is generally known to be involved in protein-protein interactions. Within TFIIH p34 strongly interacts with p44, a positive regulator of the helicase XPD. Putative protein-protein interfaces are analyzed and possible binding sites for the p34-p44 interaction suggested. KW - sequence motif analysis KW - iodides KW - protein-protein interactions KW - protein domains KW - molecular structure KW - electron density KW - protein structure KW - crystal structure Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-119471 SN - 1932-6203 VL - 9 IS - 7 ER - TY - JOUR A1 - Goos, Carina A1 - Dejung, Mario A1 - Janzen, Christian J. A1 - Butter, Falk A1 - Kramer, Susanne T1 - The nuclear proteome of Trypanosoma brucei JF - PLoS ONE N2 - Trypanosoma brucei is a protozoan flagellate that is transmitted by tsetse flies into the mammalian bloodstream. The parasite has a huge impact on human health both directly by causing African sleeping sickness and indirectly, by infecting domestic cattle. The biology of trypanosomes involves some highly unusual, nuclear-localised processes. These include polycistronic transcription without classical promoters initiated from regions defined by histone variants, trans-splicing of all transcripts to the exon of a spliced leader RNA, transcription of some very abundant proteins by RNA polymerase I and antigenic variation, a switch in expression of the cell surface protein variants that allows the parasite to resist the immune system of its mammalian host. Here, we provide the nuclear proteome of procyclic Trypanosoma brucei, the stage that resides within the tsetse fly midgut. We have performed quantitative label-free mass spectrometry to score 764 significantly nuclear enriched proteins in comparison to whole cell lysates. A comparison with proteomes of several experimentally characterised nuclear and non-nuclear structures and pathways confirmed the high quality of the dataset: the proteome contains about 80% of all nuclear proteins and less than 2% false positives. Using motif enrichment, we found the amino acid sequence KRxR present in a large number of nuclear proteins. KRxR is a sub-motif of a classical eukaryotic monopartite nuclear localisation signal and could be responsible for nuclear localization of proteins in Kinetoplastida species. As a proof of principle, we have confirmed the nuclear localisation of six proteins with previously unknown localisation by expressing eYFP fusion proteins. While proteome data of several T. brucei organelles have been published, our nuclear proteome closes an important gap in knowledge to study trypanosome biology, in particular nuclear-related processes. KW - Trypanosoma KW - gambiense KW - Trypanosoma brucei KW - proteomes KW - yellow fluorescent protein KW - mitochondria KW - protein structure KW - histones Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-158572 VL - 12 IS - 7 ER -