Heinz Neumann

• Dr.
• Professor at Darmstadt University of Applied Sciences

N(epsilon)-acetylation of lysine (1) is a reversible post-translational modification with a regulatory role that rivals that of phosphorylation in eukaryotes. No general methods exist to synthesize proteins containing N(epsilon)-acetyllysine (2) at defined sites. Here we demonstrate the site-specific incorporation of N(epsilon)-acetyllysine in reco...

Chromosome Condensation The forces that shape the structure of the highly condensed metaphase chromosomes seen during cell division in eukaryotes are still largely unknown. In vitro evidence suggests that the amino-terminal tails of the histones—such as interaction of the histone H4 tail with H2A-H2B—play an important role in chromosome hyperconden...

Lysine deacetylases (KDACs) play important roles in many physiological processes and are implicated in many human diseases. Hence, the search for modulators of KDACs is very active and reliable assays to monitor their activity are key to success. Here, we describe a new KDAC assay based on Firefly luciferase harboring an acetylation on an essen-tia...

Sirtuins are signaling hubs orchestrating the cellular response to various stressors with roles in all major civilization diseases. Sirtuins remove acyl groups from lysine residues of proteins, thereby controlling their activity, turnover, and localization. The seven human sirtuins, SirT1-7, are closely related in structure, hindering the developme...

Lysine acylations, a family of diverse protein modifications varying in acyl‐group length, charge, and saturation, are linked to many important physiological processes. Only a small set of substrate‐promiscuous lysine acetyltransferases and deacetylases (KDACs) install and remove this vast variety of modifications. Engineered KDACs that remove only...

Lamins are intermediate filaments that assemble in a meshwork at the inner nuclear periphery of metazoan cells. The nuclear periphery fulfils important functions by providing stability to the nuclear membrane, connecting the cytoskeleton with chromatin, and participating in signal transduction. Mutations in lamins interfere with these functions and...

Lysine acylation is a ubiquitous protein modification that controls various aspects of protein function, such as the activity, localization, and stability of enzymes. Mass spectrometric identification of lysine acylations has witnessed tremendous improvements in sensitivity over the last decade, facilitating the discovery of thousands of lysine acy...

In addition to acetylation, histones are modified by a series of competing longer-chain acylations. Most of these acylation marks are enriched and co-exist with acetylation on active gene regulatory elements. Their seemingly redundant functions hinder our understanding of histone acylations’ specific roles. Here, by using an acute lymphoblastic leu...

Multiple reports over the past 2 years have provided the first complete structural analyses for the essential yeast chromatin remodeler, RSC, providing elaborate molecular details for its engagement with the nucleosome. However, there still remain gaps in resolution, particularly within the many RSC subunits that harbor histone binding domains. Sol...

Lysine acetylation is a ubiquitous modification permeating the proteomes of organisms from all domains of life. Lysine deacetylases (KDACs) reverse this modification by following two fundamentally different enzymatic mechanisms, which differ mainly by the need for NAD⁺ as stoichiometric co-substrate. KDACs are often found as catalytic subunit in pr...

During mitosis, chromosomes are compacted in length by over 100-fold into rod-shaped forms. In yeast, this process depends on the presence of a centromere, which promotes condensation in cisby recruiting mitotic kinases such as Aurora B kinase. This licensing mechanism enables the cell to discriminate chromosomal from non-centromeric DNA and to pro...

Mitotic chromosome compaction is licensed by kinetochores in yeast. Recruitment of Aurora kinase B elicits a cascade of events starting with phosphorylation of H3 S10, which signals the recruitment of lysine deacetylase Hst2 and the removal of H4 K16ac. The unmasked H4 tails interact with the acidic patch of neighbouring nucleosomes to drive short-...

Chromatin remodelling complexes are multi-subunit nucleosome translocases that reorganize chromatin in the context of DNA replication, repair and transcription. To understand how these complexes find their target sites on chromatin, we use genetically encoded photo-crosslinker amino acids to map the footprint of Sth1, the catalytic subunit of the R...

Chromatin remodeler (CR) complexes play crucial roles in regulating chromosomal architectural and act to modify nucleosomal DNA contacts by repositioning nucleosomes. The mechanistic details of the CR family of proteins are of importance because each remodeler complex contributes to unique chromatin structural maintenance. Here, we study the RSC co...

Chromatin remodelling complexes are multi-subunit nucleosome translocases that reorganize chromatin in the context of DNA replication, repair and transcription. A key question is how these complexes find their target sites on chromatin. Here, we use genetically encoded photo-crosslinker amino acids to map the footprint of Sth1, the catalytic subuni...

Zelluläre Proteine zeigen komplexe Lysinacylierungsmuster, die von einem kleinen Satz Substrat‐promisker Lysindeacetylasen (KDACs) reguliert werden. Mit einer neuen Strategie lassen sich KDAC‐Varianten mit erhöhter Selektivität gegenüber spezifischen Acylierungen durch gerichtete Evolution unter Verwendung eines neuartigen Selektionssystems erhalte...

Lysine acetylation, including related lysine modifications such as butyrylation and crotonylation, is a widespread post-translational modification with important roles in many important physiological processes. However, uncovering the regulatory mechanisms that govern the reverse process, deacylation, has been challenging to address, in great part...

Serine phosphorylation is frequently used to control the activity of proteins. Eukaryotic cells employ cascades of these phosphorylation events to encode and distribute information. In this issue of Cell Chemical Biology, Beránek et al. (2018) report the creation of a system to genetically incorporate phosphoserine in mammalian cells, thereby circu...

Metabolic activity and epigenetic regulation of gene expression are intimately coupled. The mechanisms linking the two are incompletely understood. Sirtuins catalyse the removal of acetyl groups from lysine side chains of proteins using NAD+ as a stoichiometric cofactor, thereby connecting the acetylation state of histones to energy supply of the c...

The genetic incorporation of unnatural amino acids (UAAs) into proteins by amber suppression technology provides unique avenues to study protein structure, function and interactions both in vitro and in living cells and organisms. This approach has been particularly useful for studying mechanisms of epigenetic chromatin regulation, since these exte...

The installation of unnatural amino acids into proteins of living cells is an enabling technology that facilitates an enormous number of applications. UV-activatable crosslinker amino acids allow the formation of a covalent bond between interaction partners in living cells with nearly perfect spatial and temporal control. Here, we describe how this...

Post-translational modifications (PTMs) play a key role in regulating protein function, yet their identification is technically demanding. Here, we present a straightforward workflow to systematically identify post-translationally modified proteins based on two-dimensional gel electrophoresis. Upon colloidal Coomassie staining the proteins are part...

During eukaryotic cell division, nuclear chromatin undergoes marked changes with respect to shape and degree of compaction. Although already significantly compacted during interphase, upon entry into mitosis chromatin further condenses and individualizes to discrete chromosomes that are captured and moved independently by the mitotic spindle appara...

Cells control the size of their compartments relative to cell volume but there is also size control within each organelle. Yeast vacuoles neither burst nor do they collapse into a ruffled morphology, indicating that the volume of the organellar envelope is adjusted to the amount of content. It is poorly understood how this adjustment is achieved. W...

The expansion of the genetic code for the incorporation of unnatural amino acids (UAAs) in proteins of bacteria, yeasts, mammalian cells or whole animals provides molecular and structural biologists with an amazing kit of novel tools. UAAs can be used to investigate the structure and dynamics of proteins, to study their interactions or to control t...

Histone H3 trimethylation of lysine 9 (H3K9me3) and proteins of the heterochromatin protein 1 (HP1) family are hallmarks of heterochromatin, a state of compacted DNA essential for genome stability and long-term transcriptional silencing. The mechanisms by which H3K9me3 and HP1 contribute to chromatin condensation have been speculative and controver...

List of pairs of chemically crosslinked residues of hHP1β and core histones within H3 K9me3 oligonucleosomes using 1-Ethyl-3-[dimethylaminopropyl] carbodimine (EDC) identified by mass spectrometry.

Supplementary Figures 1-12, Supplementary Tables 1-3, Supplementary Note 1, Supplementary Methods and Supplementary References

Histone chaperones assist nucleosomal rearrangements to facilitate the passage of DNA and RNA polymerases through chromatin. The FACT (facilitates chromatin transcription) complex is a conserved histone chaperone involved in transcription, replication and repair. The complex consists of two major subunits, Spt16 and SSRP1/Pob3 in mammals and yeast,...

The nuclear pore complex mediates nucleocytoplasmic transport of macromolecules in eukaryotic cells. Transport through the pore is restricted by a hydrophobic selectivity filter comprising disordered phenylalanine-glycine-rich repeats of nuclear pore proteins. Exchange through the pore requires specialized transport receptors, called exportins and...

Posttranslational modifications of proteins are important modulators of protein function. In order to identify the specific consequences of individual modifications, general methods are required for homogenous production of modified proteins. The direct installation of modified amino acids by genetic code expansion facilitates the production of suc...

Incorporation of multiple different unnatural amino acids into the same polypeptide remains a significant challenge. Orthogonal ribosomes, which are evolvable as they direct the translation of a single dedicated orthogonal mRNA, can provide an avenue to produce such polypeptides routinely. Recent advances in engineering orthogonal ribosomes have cr...

TRIM21 ("tripartite motif-containing protein 21″, Ro52) is a ubiquitously expressed cytosolic Fc receptor, which has a potent role in protective immunity against non-enveloped viruses. TRIM21 mediates intracellular neutralization of antibody-coated viruses, a process called ADIN (antibody-dependent intracellular neutralization). Our results reveal...

There is provided a method for evolving an orthogonal rRNA molecule, comprising the steps of: providing one or more libraries of mutant orthogonal rRNA molecules and introducing the libraries into cells such that the orthogonal rRNA is incorporated into ribosomes to provide orthogonal ribosomes; providing one or more orthogonal mRNA molecules which...

There is provided a method for evolving an orthogonal rRNA molecule, comprising the steps of: providing one or more libraries of mutant orthogonal rRNA molecules and introducing the libraries into cells such that the orthogonal rRNA is incorporated into ribosomes to provide orthogonal ribosomes; providing one or more orthogonal mRNA molecules which...

With few minor variations, the genetic code is universal to all forms of life on our planet. It is difficult to imagine that one day organisms might exist that use an entirely different code to translate the information of their genome. Recent developments in the field of synthetic biology, however, have opened the gate to their creation. The genet...

Many anticancer therapies function largely by inducing DNA double-strand breaks (DSBs) or altering the ability of cancer cells to repair them. Proper and timely DNA repair requires dynamic changes in chromatin assembly and disassembly characterized by histone H3 lysine 56 acetylation (H3K56ac) and phosphorylation of the variant histone H2AX (γH2AX)...

Synthetic biology is the attempt to apply the concepts of engineering to biological systems with the aim to create organisms with new emergent properties. These organisms might have desirable novel biosynthetic capabilities, act as biosensors or help us to understand the intricacies of living systems. This approach has the potential to assist the d...

Cyclophilin A (CypA) is a ubiquitous cis-trans prolyl isomerase with key roles in immunity and viral infection. CypA suppresses T-cell activation through cyclosporine complexation and is required for effective HIV-1 replication in host cells. We show that CypA is acetylated in diverse human cell lines and use a synthetically evolved acetyllysyl-tRN...

The genetic code sets the correspondence between codons and the amino acids they encode in protein translation. The code is enforced by aminoacyl-tRNA synthetase/tRNA pairs, which direct the unique coupling of specific amino acids with specific anticodons. The evolutionary record suggests that a primitive genetic code expanded into the current gene...

The in vivo, genetically programmed incorporation of designer amino acids allows the properties of proteins to be tailored with molecular precision. The Methanococcus jannaschii tyrosyl-transfer-RNA synthetase-tRNA(CUA) (MjTyrRS-tRNA(CUA)) and the Methanosarcina barkeri pyrrolysyl-tRNA synthetase-tRNA(CUA) (MbPylRS-tRNA(CUA)) orthogonal pairs have...

Nucleosomes form the basic unit of DNA compaction in eukaryotes. Not only do they condense the DNA, nucleosomes also play a crucial role in gene regulation: they modulate access to nucleosomal DNA for DNA-processing proteins. DNA within the nucleosome is made accessible via a combination of conformational changes caused by spontaneous fluctuations...

Lysine acetylation of histones defines the epigenetic status of human embryonic stem cells and orchestrates DNA replication, chromosome condensation, transcription, telomeric silencing, and DNA repair. A detailed mechanistic explanation of these phenomena is impeded by the limited availability of homogeneously acetylated histones. We report a gener...

Lysine methylation is an important post-translational modification of histone proteins that defines epigenetic status and controls heterochromatin formation, X-chromosome inactivation, genome imprinting, DNA repair, and transcriptional regulation. Despite considerable efforts by chemical biologists to synthesize modified histones for use in deciphe...

We demonstrate that an orthogonal Methanosarcina barkeri MS pyrrolysyl-tRNA synthetase/tRNA(CUA) pair directs the efficient, site-specific incorporation of N6-[(2-propynyloxy)carbonyl]-L-lysine, containing a carbon-carbon triple bond, and N6-[(2-azidoethoxy)carbonyl]-L-lysine, containing an azido group, into recombinant proteins in Escherichia coli...

Polyphosphate (polyP) occurs ubiquitously in cells, but its functions are poorly understood and its synthesis has only been characterized in bacteria. Using x-ray crystallography, we identified a eukaryotic polyphosphate polymerase within the membrane-integral vacuolar transporter chaperone (VTC) complex. A 2.6 angstrom crystal structure of the cat...

Nucleosomes form the basic unit of DNA compaction in eukaryotes. Besides condensing the DNA, nucleosomes play a crucial role in gene regulation by modulating access to the nucleosomal DNA for DNA-processing proteins. Accessibility of DNA within the nucleosome can be realized by spontaneous unwrapping (DNA breathing), and by ATP-dependent remodeling...

Posttranslational modification of tyrosine residues in proteins, to produce 3-nitrotyrosine (3-NT), is associated with over 50 disease states including transplant rejection, lung infection, central nervous system and ocular inflammation shock, cancer, and neurological disorders (for example, Alzheimer's disease, Parkinson's disease, and stroke). Th...

In vivo incorporation of unnatural amino acids by amber codon suppression is limited by release factor-1-mediated peptide chain termination. Orthogonal ribosome-mRNA pairs function in parallel with, but independent of, natural ribosomes and mRNAs. Here we show that an evolved orthogonal ribosome (ribo-X) improves tRNA(CUA)-dependent decoding of amb...

Microautophagy involves direct invagination and fission of the vacuolar/lysosomal membrane under nutrient limitation. This occurs by an autophagic tube, a specialized vacuolar membrane invagination that pinches off vesicles into the vacuolar lumen. In this study we have identified the VTC (vacuolar transporter chaperone) complex as required for mic...

Frequently bacteria are exposed to membrane-damaging cationic antimicrobial molecules (CAMs) produced by the host's immune system (defensins, cathelicidins) or by competing microorganisms (bacteriocins). Staphylococcus aureus achieves CAM resistance by modifying anionic phosphatidylglycerol with positively charged L-lysine, resulting in repulsion o...

Vtc proteins have genetic and physical relations with the vacuolar H(+)-ATPase (V-ATPase), influence vacuolar H(+) uptake and, like the V-ATPase V(0) sectors, are important factors in vacuolar membrane fusion. Vacuoles from vtc1delta and vtc4delta mutants had slightly reduced H(+)-uptake activity. These defects could be separated from Vtc function...

Small conductance Ca(2+)-activated potassium (SK) channels underlie the afterhyperpolarization that follows the action potential in many types of central neurons. SK channels are voltage-independent and gated solely by intracellular Ca(2+) in the submicromolar range. This high affinity for Ca(2+) results from Ca(2+)-independent association of the S...

Thesis (doctoral)--Eberhard-Karls-Universität zu Tübingen, 2005.