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Binding site optimisation for artificial enzymes by diffusion NMR of small molecules
Catherine E Atkinson1, Abil E Aliev, William B Motherwell
1Department of Chemistry, University College London, 20 Gordon Street, UK.
Chemistry (Weinheim an Der Bergstrasse, Germany)
|April 17, 2003
Summary
Researchers designed artificial enzymes using diffusion NMR to study small molecule binding. They found that dipeptides with basic residues, like Arg-Arg, bind strongly to transition state analogues, enabling efficient ester hydrolysis catalysis.
Area of Science:
- Biophysical Chemistry
- Enzyme Design
- Supramolecular Chemistry
Background:
- Developing artificial enzymes requires understanding small molecule binding interactions.
- Transition state analogues (TSAs) are crucial for mimicking enzyme active sites.
- Diffusion NMR is a powerful technique for studying molecular interactions.
Purpose of the Study:
- To optimize binding sites for artificial enzyme design.
- To identify small molecules that bind effectively to a specific TSA.
- To investigate the catalytic potential of identified binding motifs.
Main Methods:
- Utilized diffusion NMR to measure changes in diffusion coefficients of dipeptides upon binding to a phosphonate ester TSA.
- Screened nine dipeptides with varying functional groups (basic, hydroxyl, aliphatic).
- Determined binding constants for dipeptides and a functionalized polymer with the TSA.
Main Results:
- Dipeptides with basic residues exhibited higher affinity to the TSA compared to those with hydroxyl or aliphatic groups.
- H-Arg-Arg-OH showed the most significant binding affinity (K = 86 L M⁻¹).
- A polyallylamine-based polymer with Arg-Arg sites demonstrated strong binding (K ≥ 1500 L M⁻¹) and catalytic activity.
Conclusions:
- Basic residues, particularly Arg-Arg, are effective for TSA binding site design in artificial enzymes.
- Polymer-supported Arg-Arg motifs can significantly accelerate ester hydrolysis.
- This study provides a protocol for designing efficient artificial enzymes through optimized small molecule binding.