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cisPro stabilization in prolyl carbamates influenced by tetrel bonding interactions
Shreya Banerjee1, Shama Tumminakatti1, Sudip Ghosh1
1Department of Chemistry, Indian Institute of Science, Bangalore, Karnataka - 560012, India. eprabhak@iisc.ac.in.
Organic & Biomolecular Chemistry
|October 28, 2024
Summary
Prolyl carbamates exhibit specific charge transfer interactions, known as tetrel bonding interactions (TBIs), which stabilize their cisPro rotamers. These interactions strengthen with increased carbamate alcohol substitution and solvent polarity.
Area of Science:
- Organic Chemistry
- Computational Chemistry
- Structural Biology
Background:
- Prolyl carbamates are important structural motifs in peptides and pharmaceuticals.
- Understanding rotamer preferences is crucial for predicting molecular conformation and function.
- Subtle non-covalent interactions can significantly influence conformational stability.
Purpose of the Study:
- To investigate the nature of interactions stabilizing cisPro rotamers in homologous prolyl carbamates.
- To elucidate the role of charge transfer tetrel bonding interactions (TBIs) in conformational preference.
- To determine factors influencing the strength and prevalence of these stabilizing interactions.
Main Methods:
- Nuclear Magnetic Resonance (NMR) spectroscopy for experimental analysis.
- Quantum chemical calculations for theoretical modeling and interaction analysis.
- Systematic variation of carbamate alcohol substituents and solvent polarity.
Main Results:
- NMR and theoretical analyses identified specific charge transfer tetrel bonding interactions (TBIs) in cisPro rotamers.
- These TBIs involve carbonyl-carbonyl (n → π*) and intra-carbamate (n → σ*) charge transfers.
- The number of TBIs and cisPro stability increased with more Cβ groups on the carbamate alcohol.
- Increased solvent polarity enhanced the relative stability of cisPro carbamates.
Conclusions:
- Charge transfer tetrel bonding interactions are key determinants of cisPro rotamer stability in prolyl carbamates.
- Molecular structure (Cβ substitution) and environment (solvent polarity) modulate these stabilizing interactions.
- This study provides insights into the conformational control of peptide and small molecule structures.
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