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Printable Handouts
Navigable Slide Index
- Introduction
- Repeat proteins
- Why undertake protein design
- Repeat protein vs. globular protein
- Tetratricopeptide repeat (TPR)
- Genomic distribution of proteins with tandem TPRs
- Consensus design of a TPR motif
- CTPR1, CTPR2 and CTPR3
- Introducing co-variation, enhancing stability
- Describing TPR stability by a simple model
- Lots of proteins are needed for a model
- Stability as a function of number of tandem TPRs
- Predictions of the Ising model
- Protein stability on a residue-specific basis
- Protein stability - a range of stability
- Other behaviors explained by the Ising model
- What do the long TPRs look like?
- Crystal structure of CTPR8
- Use of crystal structure of CTPR8
- Super-position of TPR domain of OGT and CTPR8
- Functional design: ligand binding
- Functional design: specific contacts
- The nature of ligand-binding sites in proteins
- CTPR - conserved and active residues
- Hypervariability defines the ligand-binding site
- Analogous to antibody hypervariable regions
- Hypervariablity and binding site - general result?
- Hypervariablity and binding site is a general result
- ANK repeats
- Ligand binding to ANK repeats - binding specificitiy
- Functional design
- Electrostatic interactions modulate binding affinity
- Binding is specific
- Split GFP detection of protein-protein intercations
- Split GFP reports on affinity and specificity
- Identifying TPR domains with novel specificities
- Summary
Topics Covered
- Repeat proteins versus globular proteins
- Consensus design, the role of conserved hydrophobic residues
- Co-variation can modulate stability, but is not essential to specify a stable fold
- Structure and stability of the designed CTPR proteins
- The thermodynamic behavior of repeat proteins in terms of a 1D Ising model
- Amide H-exchange to study stability on a residue specific basis
- The structure of long TPRs
- Hypervariability defines the ligand binding site: a general result
- Functional TPR designs
- Useful designer proteins
- The awesome power of screens and selections
Talk Citation
Regan, L. (2015, August 24). Folding and design of helical repeat proteins [Video file]. In The Biomedical & Life Sciences Collection, Henry Stewart Talks. Retrieved December 22, 2024, from https://doi.org/10.69645/POGJ8178.Export Citation (RIS)
Publication History
Financial Disclosures
- Prof. Lynne Regan has not informed HSTalks of any commercial/financial relationship that it is appropriate to disclose.
A selection of talks on Methods
Transcript
Please wait while the transcript is being prepared...
0:00
Hello. This is Lynne Regan and I'm going to be talking to you about protein design,
in particular folding and design of helical repeat proteins.
I'm going to be using our work on TPRs,
tetratricopeptide repeats to illustrate various aspects of protein design,
and to show with specific examples from our work what we can learn from this approach.
0:22
First, I need to just introduce you to
repeat proteins and contrast them with globular proteins.
This first slide, we're looking at four different types of repeat protein;
TPR, HEAT, Leucine rich repeat, Ankyrin repeat.
Which you may well have come across because they're widely distributed throughout nature,
and perform a variety of different functions in a variety of cellular pathways.
And what they typically do is to bind and interact with other molecules,
and aid for complex machines,
and complex arrangements of proteins to perform particular functions.
And it's reasonable to speculate that
their elongated structure helps them to perform these functions,
because it exposes a larger surface area than is possible in globular proteins.
If you look at the green-colored repeat units,
which are evident in the TPR, HEAT,
and Ankyrin repeats particularly,
you'll see that the basic unit is about 20 to 40 amino acids long.
And, to create the protein,
there is a direct repeat in tandem of different numbers of those repeats.
Shown on the picture here are three tandem repeats,
the TPR, many more of the HEAT and five for the Ankyrin repeat.
1:36
There are two reasons that we undertake protein design.
One is to better understand the behavior of natural proteins.
If we can recapitulate all the structural and physical properties
of proteins then we really truly understand how they are put together.
This is a kind of a different approach to those in which we take a natural protein,
and so tinker with its structure and properties by making one or two mutations.
This is kind of starting from scratch and building up.
The second reason for undertaking protein design is
to create proteins with novel interesting activities.
And this of course, is a very exciting aspect that we could make
new proteins that will perform new functions and be useful.