Inhibition of bacterial neuraminidase as a control mechanism for S.pheumoniae
Lab rotation project description
The 7 week rotation project would involve the amplification of the nanA gene for recombinant protein development. This will include the design of PCR primers, bacterial culture, DNA extraction and analysis techniques.
Week 1-2: Design PCR primers, learn bacterial culture techniques
Week 3-4: Extract bacterial DNA, amplify nanA gene by PCR and purify DNA for cloning
Week 5-6: Cloning and expression analysis nanA protein
Week 7: lab report/write up and presentation of results to lab group.
Molecules, cells and organisms
School of Veterinary Medicine and Science
Linked PhD Project Outline
Streptococcus pneumoniae is the most common bacterial respiratory pathogen in the UK and one of the major causes of mortality in children under 5 years of age in developing countries. Neuraminidases (NA) are encoded by a wide variety of mucosal pathogens and function to cleave sialic acids on cell surfaces as part of the final stage of viral replication or alternatively they act as metabolic substrates for a number of commensal and pathogenic bacteria, including those in the respiratory tract.
For bacteria, the neuraminidase gene product (nanA) cleaves sialic acid to N-Acetylmannosamine and pyruvate, which is converted to fructose 6-phosphate and ammonia and can then be used as substrates for central metabolism. For viruses such as influenza A, the sialic acid proteins on cell surfaces are used for viral attachment and the virus is released from these cells after replication by the cleavage activity of viral NA proteins. The most well studied NA protein is from influenza A virus and several commercially available NA inhibitors have been developed. These drugs work by blocking the active site on the NA, preventing the final stage of the influenza A replication cycle, but each has a slightly different structure, administration route or dosage requirement..Studies have also shown that treatment with an NA inhibitor can improve the survival of mice in influenza/S. pneumoniae co-infection studies, by blocking the action of the S. pneumoniae NA. Bacterial neuraminidase proteins are also important for biofilm formation and bacterial release from biofilms can be triggered by viral infection in the host. The gene responsible for NA production in S. pneumoniae, nanA, has been identified, however little information about the protein structure or drug interactions exist. We have recently generated an S. pneumoniae insertional mutant bacterial library, which provides the resource for isolating nanA deficient bacterial mutants and other genes important in viral/protein co-infection and are able to rapidly produce recombinant proteins in E. coli using our exiting His-tagged protein expression protocols. Purified recombinant NA will be used to assess the binding of commercially available NA inhibitors using a combination of surface plasmon resonance, isothermal titration calorimetry and protein crystallography to better understand the S. pneumoniae NA protein and inhibitor interactions. This will be used in conjunction with protein–inhibitor interaction modelling technology to determine if synthetic inhibitors can be generated for individual bacterial neuraminidases for a more targeted treatment approach to pneumococcal infection. The aim of this project is to investigate into the role of NA inhibitors in prevention of NA activity and biofilm production in S. pneumoniae infections.
Neuraminidase inhibitors limit biofilm formation and neuraminidase activity of S. pneumoniae
- To investigate the effect of commercially available neuraminidase inhibitors on S. pneumoniae in terms of (i) neuraminidase activity, (ii) biofilm formation and (iii) infection of respiratory cell lines.
- To assess specific interactions of bacterial NA and inhibitors through protein binding analysis and utilise 3D protein modelling and fragment analysis to determine improved NA and inhibitor development.