81201-85-6Relevant academic research and scientific papers
Quantitative Analysis of Multiplex H-Bonds
Arkin, Isaiah T.,Brielle, Esther S.
, p. 14150 - 14157 (2020)
H-bonding is the predominant geometrical determinant of biomolecular structure and interactions. As such, considerable analyses have been undertaken to study its detailed energetics. The focus, however, has been mostly reserved for H-bonds comprising a single donor and a single acceptor. Herein, we measure the prevalence and energetics of multiplex H-bonds that are formed between three or more groups. We show that 92% of all transmembrane helices have at least one non-canonical H-bond formed by a serine or threonine residue whose hydroxyl side chain H-bonds to an over-coordinated carbonyl oxygen at position i-4, i-3, or i in the sequence. Isotope-edited FTIR spectroscopy, coupled with DFT calculations, enables us to determine the bond enthalpies, pointing to values that are up to 127% higher than that of a single canonical H-bond. We propose that these strong H-bonds serve to stabilize serine and threonine residues in hydrophobic environments while concomitantly providing them flexibility between different configurations, which may be necessary for function.
Late-stage deuteration of 13C-enriched substrates for: T 1 prolongation in hyperpolarized 13C MRI
Taglang, Céline,Korenchan, David E.,Von Morze, Cornelius,Yu, Justin,Najac, Chloé,Wang, Sinan,Blecha, Joseph E.,Subramaniam, Sukumar,Bok, Robert,Vanbrocklin, Henry F.,Vigneron, Daniel B.,Ronen, Sabrina M.,Sriram, Renuka,Kurhanewicz, John,Wilson, David M.,Flavell, Robert R.
supporting information, p. 5233 - 5236 (2018/05/28)
A robust and selective late-stage deuteration methodology was applied to 13C-enriched amino and alpha hydroxy acids to increase spin-lattice relaxation constant T1 for hyperpolarized 13C magnetic resonance imaging. For the five substrates with 13C-labeling on the C1-position ([1-13C]alanine, [1-13C]serine, [1-13C]lactate, [1-13C]glycine, and [1-13C]valine), significant increase of their T1 was observed at 3 T with deuterium labeling (+26%, 22%, +16%, +25% and +29%, respectively). Remarkably, in the case of [2-13C]alanine, [2-13C]serine and [2-13C]lactate, deuterium labeling led to a greater than four fold increase in T1. [1-13C,2-2H]alanine, produced using this method, was applied to in vitro enzyme assays with alanine aminotransferase, demonstrating a kinetic isotope effect.
Stereoselective synthesis of stable isotope-labeled L-α-amino acids: Electrophilic amination of oppolzer's acyl sultams in the synthesis of L-[15N]alanine, L-[15N]valine, L-[15N]leucine, L-[15N]phenylalanine and
Lodwig,Unkefer
, p. 239 - 248 (2007/10/03)
Using 1-chloro-1-[15N]nitrosocyclohexane, we have prepared five L-[α-15N]amino acids. The stereoselective electophillic hydroxyamination of (S)-acylbornane-10,2-sultams, followed by Zn(o)/H+ reduction, and alkaline cleavag
