Author: Patrick
Publication: Structure and polymorphism of toxic huntingtin exon1 fibrils (Nature Comm.)
Congratulations to lab alum Dr. Hsiang-Kai Lin, graduate student Jennifer Boatz, and our collaborators locally and abroad! Our new publication describing the structure and properties of mutant huntingtin exon 1 fibrils has been published in the journal Nature Communications. The paper describes our ongoing studies of the mutant protein behind the devastating neurodegeneration in Huntington’s Disease. Biochemical and structural experiments show that mutant huntingtin exon 1 forms at least two types of neurotoxic aggregates with different internal structures. Through the use of solid-state NMR spectroscopy and electron microscopy we look at the molecular details of these structural differences. Various other disease-related amyloid proteins have a similar tendency to form different types of aggregates (i.e. amyloid polymorphism), usually mediated by changes in the β-sheets of the amyloid assemblies they form. Surprisingly, in these huntingtin aggregates the polymorphism is due primarily to supramolecular change in the interactions among exposed and dynamic non-amyloid “flanking” domains. Importantly, it is these flanking domains that are targeted by protective chaperones, but they also mediate interactions with cellular membranes that may contribute to the toxic mechanism.
Publication info: Lin H-K, Boatz JC, Krabbendam IE, et al (2017) Fibril polymorphism affects immobilized non-amyloid flanking domains of huntingtin exon1 rather than its polyglutamine core. Nat Commun 8:15462.
Postdoctoral positions available
Postdoctoral positions are available in our lab or the lab of our collaborator Rajesh Ramachandran at Case Western Reserve University in nearby Cleveland. Potential projects focus on polyglutamine-related protein aggregation or mitochondrial protein-lipid interactions involved in either mitochondrial apoptosis or mitochondrial fission.
More information about the collaborative position can be found here. Otherwise, please contact Patrick van der Wel via email with your CV and a description of your research background and interests. A background in NMR is strongly preferred.
Publication: Amorphous protein aggregates related to cataracts.
Congratulations to Jennifer Boatz, Dr. Mingyue Li and our collaborators in the Gronenborn lab for the publication of our new paper on cataract-related protein aggregation. Our newly published report in Nature Communications looks at the structure of a mutant protein (P23T γD crystallin) associated with inherited cataract disease, when it is aggregated. Interestingly, the same protein forms very different kinds of deposits depending on the conditions under which it aggregates: a common type of aggregate “polymorphism”. In many studies of protein aggregation, the protein of interest is made to form aggregates by exposure to acidic conditions. This cataract protein also aggregates well under such conditions, which cause it to form worm-like amyloid fibrils. However, Jennifer also looked at the protein aggregation that happens at neutral pH, such as is present in the eye. Interestingly, this results in amorphous-looking deposits that are dramatically different from canonical amyloid. Despite looking amorphous, the aggregates give beautiful solid-state NMR spectra that reveal their internal structure to be well ordered and seemingly very similar to the native state of the protein. (Which is not the case in amyloids that form due to extensive misfolding of other proteins) The paper also talks about the potential implications for our thinking about how the cataract-related aggregation process may take place, and how such information may be useful for optimal anti-cataract drug design and screening efforts.
The full reference for the paper: Boatz, J.C., Whitley, M.J., Li, M., Gronenborn, A.M., & Van der Wel, P.C.A. (2017) Cataract-associated P23T γD-crystallin retains a native-like fold in amorphous-looking aggregates formed at physiological pH. Nat. Commun. 8:15137.
PS. Jennifer will at the upcoming FASEB SRC meeting on Protein Aggregation in Health and Disease to present this exciting work in person. We hope to see you there!
New Protein Misfolding Disease center featured in Pitt Chronicle.
The forthcoming official opening of the new Center for Protein Conformational Diseases was featured in the Pitt Chronicle in an article entitled “New Pitt Center Will Study Diseases Linked to Misshapen Proteins“. The Center’s website is already online, here, with listings of the faculty members and an overview of an impressive list of existing collaborative publications. This exciting new initiative further strengthens existing programs such the Pittsburgh Institute for Neurodegenerative Diseases (PIND) and the Brain Institute.
Publication: Ultracentrifugal packing of biological MAS NMR samples.
Congratulations to Abhishek and Jennifer on having our new paper accepted for publication in the Journal of Biomolecular NMR. In it Abhishek describes the use of custom-built ultracentrifuge sample packing devices for the preparation of solid-state NMR samples.
Publication info:
On the use of ultracentrifugal devices for routine sample preparation in biomolecular magic-angle-spinning NMR. Mandal, A., Boatz, J.C., Wheeler, T., and Van der Wel, P.C.A. (2017) J. Biomol. NMR in press. DOI
Access it via this sharing link: http://rdcu.be/px5r
Publication: Backbone engineering within a latent β-hairpin structure to design inhibitors of polyglutamine amyloid formation. (J. Mol. Biol.)
Our new publication together with our collaborators in the Wetzel and Horne groups is now available online at the Journal of Molecular Biology:
- Backbone engineering within a latent β-hairpin structure to design inhibitors of polyglutamine amyloid formation. Kar, K., Baker, M.A., Lengyel, G.A., Hoop, C.L., Kodali, R., Byeon, I-J., Horne, W.S., Van der Wel, P.C.A., and Wetzel, R., (2016) J. Mol. Biol. in press (DOI)
In this work, Karunakar Kar and co-workers (including Cody Hoop from our lab) combined various techniques to design and test designer-inhibitors against polyQ aggregation. The work highlights the value of structural and mechanistic understanding of the polyglutamine misfolding and aggregation process in such endeavors. (Some of these structural insights were derived from current and prior solid-state NMR studies.)
Congratulations to Abhishek for his successful PhD defense!
Congratulations to Abhishek, for defending his PhD thesis entitled “Investigations of the structural changes in proapoptotic peroxidase-active cardiolipin-bound cytochrome c and liquid-gel phase transitions in liposomes using solid state NMR spectroscopy.” Abhishek has been a PhD student in the Pitt/CMU PhD program in Molecular Biophysics & Structural Biology (MBSB).
Congratulations, Dr. Mandal!
Welcoming two new postdoctoral researchers!
We are excited to welcome two new postdoctoral researchers to the lab, who joined us this November 2016. Dr. Irina Matlahov is joining us from Bar-Ilan University in Israel, where she did her PhD research in solid-state NMR spectroscopy. Dr. Mingyue Li is joining us from the University of Delaware, where she also worked on biomolecular solid-state NMR. They will be working on our NIH-funded research projects on the protein misfolding and aggregation processes associated with Huntington’s Disease and the pivotal membrane-protein interactions implicated in mitochondrial apoptosis.
For more information, see the People page of the site.
Publication: MAS NMR studies of lipid phase behavior at low temperatures. (Biophys J)
Congratulations to Abhishek Mandal for his new paper in the Biophysical Journal. You can gain free access to the paper through the following URL (until Dec 2016). In this paper Abhishek describes his use of magic-angle-spinning NMR and differential scanning calorimetry (DSC) to look at the freezing and melting of water and lipids in hydrated membrane samples. Detecting the lipid and water proton nuclei by NMR, we observe a change in the freezing temperature of the water and the gel-liquid transition of the phospholipids (including also cardiolipin (TOCL)-containing samples). The MAS NMR sample conditions lower the freezing point of the water, but also lead to a lowering of the lipids Tm temperature. For more information read the paper here.
Reference:
MAS 1H NMR Probes Freezing Point Depression of Water and Liquid-Gel Phase Transitions in Liposomes
Abhishek Mandal, Patrick C.A. van der Wel
Biophysical Journal, Volume 111, Issue 9, 1 November 2016, Pages 1965–1973
Publication: structural and functional study of peptide-based nano-structures (JACS).
Congrats to our collaborators in the Rosi group (Pitt chemistry), the Zhang group (Struct. Biol. Dept.) and co-authors, on the acceptance of our collaborative paper in JACS, describing the structural and functional analysis of peptide-based nano-assemblies. The paper is available online as an in-press “ASAP” article on the JACS website. Jennifer and Abhishek used solid-state NMR to probe the core structure of the assembled peptides, finding a type of “intrinsic” polymorphism indicative of amyloid-like “steric zipper” motifs in these designer nanomaterials.