Bioc192 Notes: Protein Engineering & Biotechnology
Learning Objectives
- Describe how molecular mechanisms inform biotechnology methods.
- Discuss how and why we might engineer proteins for biotechnology.
- Describe examples of proteins used in biotechnology.
Applications of rDNA technologies
- Precision Medicine
- Therapeutic Applications
- Agricultural Advancements
- Environmental Conservation
Protein Engineering: How and Why
- Obj. 2: Can we design new proteins with new/improved function?
- Why design proteins: Degrade plastic waste; Improve therapeutics; Industrial applications; Research; Drug discovery and development; Agricultural and environmental applications; Precision medicine; Biodefence and biosecurity
- Pathway: Identify a need → Target selection → Design the protein → Gene synthesis → Expression and purification → Characterisation and optimisation → Validation and testing
- Predicts the 3D structure of proteins from amino acid sequence: 3D structure from sequence
- Accelerates protein design; helps identify functional domains and active sites
- Enables structure-guided engineering and protein–protein interaction modelling
- Predictions serve as a starting point for experimental work
What could we do with AlphaFold? CASE STUDIES (high-level mentions)
- Accelerating the fight against malaria
- Combatting drug-resistant bacteria
- Designing more effective drugs
- Paving the way for potential Parkinson's treatments
- Breaking down plastic pollution
- Increasing honeybees’ survival
Examples of proteins used in Biotechnology
- Therapeutic Antibodies – Cancer Therapies
- Rituximab, Trastuzumab (Herceptin), Pembrolizumab (Keytruda)
- Produced in mammalian cell culture due to glycosylation needs
- Developed via protein engineering: phage display; computational tools for properties based on sequence/structure changes
- Semaglutide (Ozempic, Wegovy)
- A GLP-1 analog to treat Type II diabetes
- Modifications to increase stability/half-life:
- First 6 amino acids removed (N-terminus) 6
- Ala8 → 2-aminoisobutyric acid
- Lys28Arg
- Acylation of Lys26 with a spacer attached to a Glu and C-18 fatty acid
- Produced in yeast
- The Impossible Burger – Haem Engineering
- Problem: plant-based meats lack haem for authentic flavour/aroma
- Solution: use soy leghaemoglobin; recombinant expression in yeast for scalability
- Sustainability impact (haem engineering):
- Uses 96 ext\% less land, 87\% less water, and produces 89\% fewer greenhouse gas emissions than beef
Key Concepts
- Expression system choice involves trade-offs in production cost/speed, post-translational modifications (glycosylation), folding, and regulatory considerations.
- AI tools (e.g., AlphaFold) predict protein structures to guide engineering; not a substitute for experimental validation.
- Engineered proteins show improved properties across applications: antibodies, GLP-1 receptor agonists, and plant-based food proteins.
Objective-based Self Assessment Questions
- What factors would you consider when choosing a system to produce a recombinant protein of interest?
- Describe the steps required to make a recombinant protein.
- In general terms, how do we engineer proteins for biotechnology?
- What computational tools can aid in protein engineering?
- What are therapeutic antibodies and what are some potential applications in which they could be useful?
- How does Semaglutide differ from endogenous GLP-1?
