2280-75-3Relevant academic research and scientific papers
Diversity of Secondary Structure in Catalytic Peptides with β-Turn-Biased Sequences
Metrano, Anthony J.,Abascal, Nadia C.,Mercado, Brandon Q.,Paulson, Eric K.,Hurtley, Anna E.,Miller, Scott J.
, p. 492 - 516 (2017/02/23)
X-ray crystallography has been applied to the structural analysis of a series of tetrapeptides that were previously assessed for catalytic activity in an atroposelective bromination reaction. Common to the series is a central Pro-Xaa sequence, where Pro is either l- or d-proline, which was chosen to favor nucleation of canonical β-turn secondary structures. Crystallographic analysis of 35 different peptide sequences revealed a range of conformational states. The observed differences appear not only in cases where the Pro-Xaa loop-region is altered, but also when seemingly subtle alterations to the flanking residues are introduced. In many instances, distinct conformers of the same sequence were observed, either as symmetry-independent molecules within the same unit cell or as polymorphs. Computational studies using DFT provided additional insight into the analysis of solid-state structural features. Select X-ray crystal structures were compared to the corresponding solution structures derived from measured proton chemical shifts, 3J-values, and 1H-1H-NOESY contacts. hese findings imply that the conformational space available to simple peptide-based catalysts is more diverse than precedent might suggest. The direct observation of multiple ground state conformations for peptides of this family, as well as the dynamic processes associated with conformational equilibria, underscore not only the challenge of designing peptide-based catalysts, but also the difficulty in predicting their accessible transition states. These findings implicate the advantages of low-barrier interconversions between conformations of peptide-based catalysts for multistep, enantioselective reactions.
Structural studies of β-turn-containing peptide catalysts for atroposelective quinazolinone bromination
Metrano,Abascal,Mercado,Paulson,Miller
, p. 4816 - 4819 (2016/04/09)
We describe herein a crystallographic and NMR study of the secondary structural attributes of a β-turn-containing tetra-peptide, Boc-Dmaa-d-Pro-Acpc-Leu-NMe2, which was recently reported as a highly effective catalyst in the atroposelective bromination of 3-arylquinazolin-4(3H)-ones. Inquiries pertaining to the functional consequences of residue substitutions led to the discovery of a more selective catalyst, Boc-Dmaa-d-Pro-Acpc-Leu-OMe, the structure of which was also explored. This new lead catalyst was found to exhibit a type I′ β-turn secondary structure both in the solid state and in solution, a structure that was shown to be an accessible conformation of the previously reported catalyst, as well.
Additivity or cooperativity: Which model can predict the influence of simultaneous incorporation of two or more functionalities in a ligand molecule?
Nasief, Nader N.,Hangauer, David
, p. 897 - 915 (2015/05/27)
Predicting how binding affinity responds to ligand structural modifications in structure-activity relationship studies (SAR) is a major challenge in medicinal chemistry. This is particularly true when two or more of these modifications are carried out simultaneously. In this study, we present binding affinity data from several series of thermolysin inhibitors in which simultaneous structural modifications were investigated to determine whether they are cooperative or additive. Data revealed that, while additivity is at work in some cases, cooperativity is more commonly demonstrated. Cooperativity and additivity were then correlated with ligand descriptors, such as the spacing and the topological features of the modified groups, in a manner that may provide guidance as to when each model should be utilized. Cooperativity was particularly associated with contiguous groups and small unbranched hydrophobic side chain. Additivity, on the other hand, was associated with moderately distant hydrophobic group combinations and side chain branching. Such correlations can improve the predictability of SAR studies and can provide a starting point for additional investigations that may lead to further significant enhancements in the current scoring functions.
Hydantoin-free synthesis of peptide ester isocyanates, isothiocyanates, and dipeptidyl ureas: The application of zinc dust in a carbonylation procedure without base
Narendra,Vishwanatha,Sureshbabu, Vommina V.
body text, p. 3247 - 3254 (2011/11/30)
Non-Schotten-Baumann conditions are described for the hydantoin-free synthesis of peptide ester isocyanates using activated zinc dust as a non-basic HCl scavenger. Also, the procedure gives no N-acylated products in the case of the conversion of amino acid and peptide amides into isocyanates. Georg Thieme Verlag Stuttgart · New York.
Inhibition of porcine pepsin by two substrate analogues containing statine. The effect of histidine at the P2 subsite on the inhibition of aspartic proteinases
Maibaum,Rich
, p. 625 - 629 (2007/10/02)
Two new inhibitors, 4 and 5, of the aspartic proteinase porcine pepsin were synthesized. These compounds, which span the P4-P'3 binding subsites of the enzyme, were derived by replacing the Nph-Phe dipeptidyl unit of a good pepsin su
