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📚 Lecture 12: In Silico Protein Engineering – Study Notes
📌 Intended Learning Outcomes (ILOs)
✔ Describe approaches for in silico mutagenesis.
✔ Explain novel site-specific mutagenesis techniques.
✔ Understand the role of 3D protein structure prediction in protein engineering.
✔ Discuss computational techniques for ligand binding orientation & binding free energy
calculation.
🛠️ Approaches to In Silico Protein Engineering
1️⃣ Rational Design
🔹 Requires knowledge of amino acid sequence, 3D structure, and protein function.
🔹 Steps in Rational Design:
1. Predict 3D structure of protein.
2. Use molecular modeling to identify key residues.
3. Perform site-directed mutagenesis (modify specific amino acids).
4. Express the modified protein in host cells.
5. Characterize function to confirm changes.
✔ Suitable for well-characterized proteins where specific residues influence function.
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2️⃣ Directed Evolution
🔹 Does NOT require prior knowledge of structure or function.
🔹 Mimics natural evolution in the lab to obtain proteins with desired properties.
🔹 Steps in Directed Evolution:
1. Introduce sequence diversity using:
• Non-recombinative methods (e.g., error-prone PCR).
• Recombinative methods (e.g., DNA shuffling, StEP).
2. Express large mutant libraries in host cells.
3. Screen & select mutants with desired functions.
4. Amplify best-performing mutants.
✔ Used when no detailed structural information is available.
3️⃣ Semi-Rational Design (Computationally Assisted Directed Evolution)
🔹 Combines elements of Rational Design & Directed Evolution.
🔹 Based on structure-function relationship of a target site.
🔹 Steps in Semi-Rational Design:
1. Predict protein structure using molecular modeling.
2. Perform site-saturation mutagenesis at key sites (using degenerate primers).
3. Express a smaller library of mutants (compared to Directed Evolution).
4. Screen & select variants with improved function.
5. Perform characterization studies.
✔ More efficient than random mutagenesis since changes are focused on functionally important
regions.
📚 Lecture 12: In Silico Protein Engineering – Study Notes
📌 Intended Learning Outcomes (ILOs)
✔ Describe approaches for in silico mutagenesis.
✔ Explain novel site-specific mutagenesis techniques.
✔ Understand the role of 3D protein structure prediction in protein engineering.
✔ Discuss computational techniques for ligand binding orientation & binding free energy
calculation.
🛠️ Approaches to In Silico Protein Engineering
1️⃣ Rational Design
🔹 Requires knowledge of amino acid sequence, 3D structure, and protein function.
🔹 Steps in Rational Design:
1. Predict 3D structure of protein.
2. Use molecular modeling to identify key residues.
3. Perform site-directed mutagenesis (modify specific amino acids).
4. Express the modified protein in host cells.
5. Characterize function to confirm changes.
✔ Suitable for well-characterized proteins where specific residues influence function.
, 2
2️⃣ Directed Evolution
🔹 Does NOT require prior knowledge of structure or function.
🔹 Mimics natural evolution in the lab to obtain proteins with desired properties.
🔹 Steps in Directed Evolution:
1. Introduce sequence diversity using:
• Non-recombinative methods (e.g., error-prone PCR).
• Recombinative methods (e.g., DNA shuffling, StEP).
2. Express large mutant libraries in host cells.
3. Screen & select mutants with desired functions.
4. Amplify best-performing mutants.
✔ Used when no detailed structural information is available.
3️⃣ Semi-Rational Design (Computationally Assisted Directed Evolution)
🔹 Combines elements of Rational Design & Directed Evolution.
🔹 Based on structure-function relationship of a target site.
🔹 Steps in Semi-Rational Design:
1. Predict protein structure using molecular modeling.
2. Perform site-saturation mutagenesis at key sites (using degenerate primers).
3. Express a smaller library of mutants (compared to Directed Evolution).
4. Screen & select variants with improved function.
5. Perform characterization studies.
✔ More efficient than random mutagenesis since changes are focused on functionally important
regions.
