Answers are grounded in this paper and cite their sources.
Cyclodipeptides containing L‐Thr and L‐His residues have been studied by 1H NMR in D2O and DMSO‐d6. In the neutral form in D2O as in DMSO‐d6, the folded form of the L‐His residue is not unique. The diketopiperazine ring seems to be not strictly planar.
No takes yet. Share an insight, caveat, or question.
Ptak et al. (1974) studied this question.
Synapse has enriched 10 related papers. Consider them for comparative context: