Increasing Enzyme Stability and Activity through Hydrogen Bond-Enhanced Halogen Bonds
| Autor: | Austin T. Alexander, Matthew R. Scholfield, Rhianon K. Rowe, Melissa Coates Ford, Anna-Carin C. Carlsson, Pui Shing Ho, Ryan A. Mehl |
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| Rok vydání: | 2018 |
| Předmět: |
Models
Molecular 0301 basic medicine Hot Temperature Substituent 010402 general chemistry 01 natural sciences Biochemistry Article 03 medical and health sciences chemistry.chemical_compound Enzyme Stability Hydrolase Bacteriophage T4 Peptide bond Halogen bond biology Hydrogen bond Active site Hydrogen Bonding 0104 chemical sciences Crystallography 030104 developmental biology chemistry Intramolecular force Halogen Mutagenesis Site-Directed biology.protein Thermodynamics Tyrosine Muramidase |
| Zdroj: | Biochemistry |
| ISSN: | 1520-4995 0006-2960 |
| DOI: | 10.1021/acs.biochem.8b00603 |
| Popis: | The construction of more stable proteins is important in biomolecular engineering, particularly in the design of biologics-based therapeutics. We show here that replacing the tyrosine at position 18 (Y18) of T4 lysozyme with the unnatural amino acid m-chlorotyrosine (mClY) increases both the thermal stability (increasing the melting temperature by ∼1 °C and the melting enthalpy by 3 kcal/mol) and the enzymatic activity at elevated temperatures (15% higher than that of the parent enzyme at 40 °C) of this classic enzyme. The chlorine of mClY forms a halogen bond (XB) to the carbonyl oxygen of the peptide bond at glycine 28 (G28) in a tight loop near the active site. In this case, the XB potential of the typically weak XB donor Cl is shown from quantum chemical calculations to be significantly enhanced by polarization via an intramolecular hydrogen bond (HB) from the adjacent hydroxyl substituent of the tyrosyl side chain, resulting in a distinctive synergistic HB-enhanced XB (or HeX-B for short) interaction. The larger halogens (bromine and iodine) are not well accommodated within this same loop and, consequently, do not exhibit the effects on protein stability or function associated with the HeX-B interaction. Thus, we have for the first time demonstrated that an XB can be engineered to stabilize and increase the activity of an enzyme, with the increased stabilizing potential of the HeX-B further extending the application of halogenated amino acids in the design of more stable protein therapeutics. |
| Databáze: | OpenAIRE |
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