Claudia's update on her PhD

– Could you give us a brief update on your project?

Actually, my project changed quite a bit from what I was doing in the beginning. I started a really ambitious project, aiming to not only crystallise a membrane protein on its own but bound to some important cellular binding partners. This sounded amazing, but also included a lot of challenges, ranging from getting the individual protein components, to isolating the complex and finally crystallise this thing. I was already struggling with the first step and soon had to admit that the goals set in the beginning would probably not be met. However, I made some good progress with some side projects I started during my secondments in Hamburg and at Novartis, which I could combine to create a new story for my thesis.

– So, what is the topic of your project now?

I’m rationalising membrane protein crystallisation!

As people who follow our network should know by now, membrane proteins are known to be notoriously difficult to crystallise, however, we still want to work on them, as they are very interesting drug targets. One very important membrane protein family for drug discovery are G-protein-coupled receptors (GPCRs). They transmit extracellular chemical and visual signals across the plasma membrane initiating a broad variety of cellular responses. Currently, over 30% of prescribed drugs target GPCRs.

Using two different model systems I’m now exploring different strategies in protein crystallisation; one for the production of microcrystals for time-resolved studies and one for the characterisation of novel GPCR ligands.

For the model enzyme aspartate α-decarboxylase, I established a robust protocol for the generation of large amounts of tiny crystals with precise regulation of crystal size. These crystals were then used for time-resolved experiments in prototypes of 3D printed microfluidic chips at a synchrotron beamline!

I’m highlighting the importance of a reliable crystallization system for drug discovery through the example of characterising the interactions of the adenosine A2A receptor with novel compounds developed by our collaborator Novartis.  To this end I prepared a stabilised receptor construct and crystallised it in complex with two different reference compounds and am now working towards solving a structure of the receptor in complex with the novel compounds.

– Did the ITN help you with redirecting your project?

My supervisors helped me a lot in restructuring my results in a way that they make up a coherent story again, which I also can bring to an end in the time remaining.

But what I valued most, is being connected to a group of people who are experiencing the same things as you do. Not getting the results expected can be very frustrating and there is no better cure against this frustration than being able to talk to your RAMP friends who remind you that you’re not alone in this and motivate you again to keep on trying.