5V7F

T4 lysozyme Y18Ymi

Summary for 5V7F

• Entry DOI: 10.2210/pdb5v7f/pdb
• Related: 5V7D 5V7E
• Descriptor: Lysozyme, 2-HYDROXYETHYL DISULFIDE (3 entities in total)
• Functional Keywords: t4 lysozyme, halogen bonds, protein engineering, unnatural amino acids, hydrolase
• Biological source: Enterobacteria phage T4
• Total number of polymer chains: 1
• Total formula weight: 19737.39

Authors

Carlsson, A.-C.C. (deposition date: 2017-03-20, release date: 2018-06-20, Last modification date: 2024-10-30)

Primary citation

Carlsson, A.C.,Scholfield, M.R.,Rowe, R.K.,Ford, M.C.,Alexander, A.T.,Mehl, R.A.,Ho, P.S.
Increasing Enzyme Stability and Activity through Hydrogen Bond-Enhanced Halogen Bonds.
Biochemistry, 57:4135-4147, 2018

PubMed Abstract: 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 ( Y) 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 Y 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.

PubMed: 29921126
DOI: 10.1021/acs.biochem.8b00603

Experimental method

X-RAY DIFFRACTION (1.65 Å)