Nucleosome assembly requires the coordinated deposition of histone complexes H3-H4 and H2A-H2B to form a histone octamer on DNA. In the current paradigm, specific histone chaperones guide the... Show moreNucleosome assembly requires the coordinated deposition of histone complexes H3-H4 and H2A-H2B to form a histone octamer on DNA. In the current paradigm, specific histone chaperones guide the deposition of first H3-H4 and then H2A-H2B. Here, we show that the acidic domain of DNA repair factor APLF (APLF(AD)) can assemble the histone octamer in a single step and deposit it on DNA to form nucleosomes. The crystal structure of the APLF(AD)-histone octamer complex shows that APLF(AD) tethers the histones in their nucleosomal conformation. Mutations of key aromatic anchor residues in APLF(AD) affect chaperone activity in vitro and in cells. Together, we propose that chaperoning of the histone octamer is a mechanism for histone chaperone function at sites where chromatin is temporarily disrupted. Show less
Nogueira, S.S.; Schlegel, A.; Maxeiner, K.; Weber, B.; Barz, M.; Schroer, M.A.; ... ; Haas, H. 2020
Polysarcosine (pSar) is a polypeptoid based on the endogenous amino acid sarcosine (N-methylated glycine), which has previously shown potent stealth properties. Here, lipid nanoparticles (LNPs) for... Show morePolysarcosine (pSar) is a polypeptoid based on the endogenous amino acid sarcosine (N-methylated glycine), which has previously shown potent stealth properties. Here, lipid nanoparticles (LNPs) for therapeutic application of messenger RNA were assembled using pSarcosinylated lipids as a tool for particle engineering. Using pSar lipids with different polymeric chain lengths and molar fractions enabled the control of the physicochemical characteristics of the LNPs, such as particle size, morphology, and internal structure. In combination with a suited ionizable lipid, LNPs were assembled, which displayed high RNA transfection potency with an improved safety profile after intravenous injection. Notably, a higher protein secretion with a reduced immunostimulatory response was observed when compared to systems based on polyethylene glycol (PEG) lipids. pSarcosinylated nanocarriers showed a lower proinflammatory cytokine secretion and reduced complement activation compared to PEGylated LNPs. In summary, the described pSar-based LNPs enable safe and potent delivery of mRNA, thus signifying an excellent basis for the development of PEG-free RNA therapeutics. Show less
The "4D Biology Workshop for Health and Disease", held on 16-17th ofMarch 2010 in Brussels, aimed at finding the best organising principlesfor large-scale proteomics, interactomics and structural... Show moreThe "4D Biology Workshop for Health and Disease", held on 16-17th ofMarch 2010 in Brussels, aimed at finding the best organising principlesfor large-scale proteomics, interactomics and structural genomics/biology initiatives, and setting the vision for future high-throughputresearch and large-scale data gathering in biological and medical science.Major conclusions of the workshop include the following. (i)Development of new technologies and approaches to data analysis iscrucial. Biophysical methods should be developed that span a broadrange of time/spatial resolution and characterise structures andkinetics of interactions. Mathematics, physics, computational andengineering tools need to be used more in biology and new tools needto be developed. (ii) Database efforts need to focus on improveddefinitions of ontologies and standards so that system-scale data andassociated metadata can be understood and shared efficiently. (iii)Research infrastructures should play a key role in fosteringmultidisciplinary research, maximising knowledge exchange betweendisciplines and facilitating access to diverse technologies. (iv)Understanding disease on a molecular level is crucial. Systemapproaches may represent a new paradigm in the search for biomarkersand new targets in human disease. (v) Appropriate education andtraining should be provided to help efficient exchange of knowledgebetween theoreticians, experimental biologists and clinicians. Theseconclusions provide a strong basis for creating major possibilities inadvancing research and clinical applications towards personalisedmedicine. Show less
