Berkeley Lab

Assembly-associated trans-to-cis amide bond isomerization with peptoid B28 nanosheets

By Annelise Barron

On Day 1 of the 2020 Annual User Meeting of the Molecular Foundry, a very exciting User Highlight talk was given by Professor Anant Paravastu from Georgia Tech’s School of Chemical and Biomolecular Engineering. Anant gave a lecture entitled, “Assembly-associated trans-to-cis amide bond isomerization with peptoid B28 nanosheets”.

The talk highlighted his collaborative research with Dr. Ronald Zuckermann, former director of the Foundry’s Biological Nanostructures facility. Ron initially approached Anant with a question and hypothesis about self-assembled peptoid nanosheets, which he believed could be addressed using Anant’s preferred experimental tools: solid-state NMR using magic angle spinning and timed NMR pulse sequences tuned to (for instance) carbon atoms within the sequence-specific polypeptoids of interest. Anant gave an extremely clear and engaging lecture in which he described how using these sophisticated solid-state NMR methods, he and Ron were able to show that whereas trans-amide peptoid backbone conformers are preferred in non-assembled peptoids, once the peptoid chains self-assemble into highly ordered nanosheets, a cis-amide backbone conformer becomes highly preferred.

While these results were initially astonishing for Anant, they fit with Ron’s molecular and physical intuition that the configuration of atoms around the peptoids’ backbone amide bond was really a key factor in nanosheet self-assembly. Overall, this was an exciting talk that highlights the way that the Molecular Foundry brings together scientists from all across America in highly interdisciplinary projects that shed new light on what is possible in nanoscience.