Dr Theodoros Karamanos
- Job title: University Academic Fellow in Nuclear Magnetic Resonance Spectroscopy
- Email: T.Karamanos@leeds.ac.uk
- Faculty: Biological Sciences
- School: Molecular and Cellular Biology
- Location: Garstang 8.52a
- Areas of expertise: NMR spectroscopy, Molecular chaperones, Short-lived excited protein states, Structural biology, Protein aggregation
- Website links: Lab page | Google scholar | ORCID
We use Nuclear Magnetic Resonance (NMR) methods to investigate complex biological mechanisms, including protein folding and misfolding, and chaperone mediated proteostasis. All of these events proceed via complex pathways that involve transient, short-lived protein species which are often critical for biological function. Solution NMR spectroscopy is the only available biophysical technique that can characterise, in atomic resolution, the structure and kinetics of formation of protein states even if these are lowly-populated (<5%). My research focuses on the development and application of NMR methods and the combination of these approaches with other biophysical techniques (fluorescence-based methods, mass spectrometry and electron microscopy), computational analysis and functional assays in-vitro and in-cells to investigate the structure and dynamics of interconverting systems.
Current major projects
- Investigating the specificity of the chaperone network
- Visualization of protein excited states at the atomic level
- Integration of structural methods to study complex biological equilibria
Detailed research programme
Unpicking the specificity of the protein quality control network
Protein homeostasis (proteostasis) is performed by molecular chaperones that are responsible for assisting protein folding, targeting misfolded proteins for degradation and disaggregation. Failure of the protein quality network is associated with various human pathologies including neurodegeneration, cancer, autoimmune deficiencies, and ageing. The ubiquitous Hsp40 (DNAJ) family acts as a master regulator of the entire chaperone network by interacting with the powerful Hsp70 machine but can also function independently. Using the DNAJB6b isoform, a potent inhibitor of protein polymerization reactions we are investigating: 1) how short parts of the Hsp40 linker region (helix 5) regulate the Hsp70 cycle, 2) what is the mechanism of reversible chaperone oligomerization 3) how specific aggregation-prone substrates are recognised.
Characterising protein excited states at atomic resolution
Proteins are not static entities. They show motions over a range of timescales (ps – ms) with some of them leading to small but significant populations of alternative/excited protein states. These short-lived conformations are often important for biological functions, with binding partners or small molecule drugs perturbing these equilibria. We use and develop NMR methods to study the structure, kinetics and thermodynamics of interconverting species. We combine these (often sparse) data with data from other biophysical techniques using sophisticated computational approaches in order to visualise transient protein states at the atomic level.