5V7D image
Entry Detail
PDB ID:
5V7D
Keywords:
Title:
T4 lysozyme Y18Ymbr
Biological Source:
Source Organism:
Host Organism:
PDB Version:
Deposition Date:
2017-03-20
Release Date:
2018-06-20
Method Details:
Experimental Method:
Resolution:
1.35 Å
R-Value Free:
0.21
R-Value Work:
0.18
R-Value Observed:
0.18
Space Group:
P 32 2 1
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:Lysozyme
Chain IDs:A
Chain Length:170
Number of Molecules:1
Biological Source:Enterobacteria phage T4
Modified Residue
Compound ID Chain ID Parent Comp ID Details 2D Image
BYR A TYR modified residue
Ligand Molecules
Primary Citation
Increasing Enzyme Stability and Activity through Hydrogen Bond-Enhanced Halogen Bonds.
Biochemistry 57 4135 4147 (2018)
PMID: 29921126 DOI: 10.1021/acs.biochem.8b00603

Abstact

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.

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Primary Citation of related structures