Simultaneous screening for protein expression and binding to facilitate protein target and lead drug validation in the biopharmaceutical industry

The ability to produce and characterize potential protein target is an essential first step in the drug discovery pipeline. If this target is difficult to handle due to poor expression, low stability or propensity it can slow or even preclude timely and cost effective drug development.  Using a method developed in our laboratory (called the Tri-Partite ß-Lactamase Assay, TPBLA) which links protein stability / aggregation resistance to bacterium’s ampicillin resistance, we have shown that directed evolution can be used to improve the stability of a protein[1-3]. This improvement in experimental tractability often comes at a cost of reduced binding partner affinity as proteins are optimized for function over stability.  

To address this problem, we have adapted the TPBLA to allow the sequential selection for “experimental tractability” of a protein and affinity for its target using orthogonal assays in the E. coli periplasm.   

In this project, which is a collaboration with UCB CellTech, we aim to assess its potential for use in an industrial setting using protein targets supplied by UCB. 

Objectives;

1. To use well-characterised cognate protein binding partners with a range of affinities to understand the relationship between Kd and sensor output response (i.e. define sensitivity and range of sensor) 
2. To use the screen to improve the biophysical properties of using target proteins provided by UCB.
3. To use the large volume of genotype-phenotype data obtained to understand the mechanism by which the test proteins show improved tractability. 

Experimental Approach:

Our screen[1-3] has been modified to allow the sorting of high and low affinity binders by FACS. Initially, model protein binding pairs with a range of affinities will be constructed. For UCB target improvement, libraries of target protein fused to the ß-lactamase construct will be generated by epPCR. Improved variants will be analysed at Leeds and UCB using a range of biophysical techniques and specific activity / inhibition assays available at UCB.

Value of an industry/academic PhD:

The studentship builds on previous collaborations between the Brockwell/Radford groups at Leeds with UCB. Collaboration is vital for this project, as the Leeds team have developed a system to address an unmet need in the pharmaceutical sector. To fully validate this system we will use apply the method to improve the tractability of industrially important target proteins. UCB will also provide all the activity and affinity assays previously optimized for each system.

Eligibility: 

You should hold a first degree equivalent to at least a UK upper-second class honours degree or a MSc degree in a relevant subject.

Applicants whose first language is not English must provide evidence that their English language is sufficient to meet the specific demands of their study. The Faculty of Biological Sciences minimum requirements in IELTS and TOEFL tests are:

• British Council IELTS - score of 6.0 overall, with no element less than 5.5
• TOEFL iBT - overall score of 87 with the listening and reading element no less than 20, writing element no less than 21 and the speaking element no less than 22.

How to apply:

To apply for this project applicants should complete an online application form and attach the following documentation to support their application. 

• a full academic CV
• degree certificate and transcripts of marks
• Evidence that you meet the University's minimum English language requirements (if applicable).

To help us identify that you are applying for this studentship please ensure you provide the following information on your application form;

• Select PhD in Biological Sciences as your programme of study
• When asked for source of funding please make it clear that you are applying for a "White Rose BBSRC DTP Studentship"
• Give the full project title and name the supervisors listed in this advert. You can be considered for up to 3 projects in total.

If you have any further queries regarding this opportunity, please contact [Email Address Removed]