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  • Development of Decreased-Gluten Wheat Enabled by Determination of the Genetic Basis of lys3a Barley PLANT PHYSIOLOGY Moehs, C. P., Austill, W. J., Holm, A., Large, T. G., Loeffler, D., Mullenberg, J., Schnable, P. S., Skinner, W., van Boxtel, J., Wu, L., McGuire, C. 2019; 179 (4): 1692–1703

    Abstract

    Celiac disease is the most common food-induced enteropathy in humans, with a prevalence of approximately 1% worldwide. It is induced by digestion-resistant, proline- and glutamine-rich seed storage proteins, collectively referred to as gluten, found in wheat (Triticum aestivum). Related prolamins are present in barley (Hordeum vulgare) and rye (Secale cereale). The incidence of both celiac disease and a related condition called nonceliac gluten sensitivity is increasing. This has prompted efforts to identify methods of lowering gluten in wheat, one of the most important cereal crops. Here, we used bulked segregant RNA sequencing and map-based cloning to identify the genetic lesion underlying a recessive, low-prolamin mutation (lys3a) in diploid barley. We confirmed the mutant identity by complementing the lys3a mutant with a transgenic copy of the wild-type barley gene and then used targeting-induced local lesions in genomes to identify induced single-nucleotide polymorphisms in the three homeologs of the corresponding wheat gene. Combining inactivating mutations in the three subgenomes of hexaploid bread wheat in a single wheat line lowered gliadin and low-molecular-weight glutenin accumulation by 50% to 60% and increased free and protein-bound lysine by 33%.

    View details for DOI 10.1104/pp.18.00771

    View details for Web of Science ID 000462993100042

    View details for PubMedID 30696748

    View details for PubMedCentralID PMC6446766

  • Selective oxidation of exogenous substrates by a bis-Cu(III) bis-oxide complex: Mechanism and scope INORGANICA CHIMICA ACTA Large, T. G., Mahadevan, V., Keown, W., Stack, T. P. 2019; 486: 782–92
  • Selective Oxidation of Exogenous Substrates by a Bis-Cu(III) Bis-Oxide Complex: Mechanism and Scope. Inorganica chimica acta Large, T. A., Mahadevan, V., Keown, W., Stack, T. D. 2019; 486: 782–92

    Abstract

    Cu(III)2(μ-O)2 bis-oxides (O) form spontaneously by direct oxygenation of nitrogen-chelated Cu(I) species and constitute a diverse class of versatile 2e-/2H+ oxidants, but while these species have attracted attention as biomimetic models for dinuclear Cu enzymes, reactivity is typically limited to intramolecular ligand oxidation, and systems exhibiting synthetically useful reactivity with exogenous substrates are limited. O tmpd (TMPD = N 1 , N 1 , N 3 , N 3 -tetramethylpropane-1,3-diamine) presents an exception, readily oxidizing a diverse array of exogenous substrates, including primary alcohols and amines selectively over their secondary counterparts in good yields. Mechanistic and DFT analyses suggest substrate oxidation proceeds through initial axial coordination, followed by rate limiting rotation to position the substrate in the Cu(III) equatorial plane, whereupon rapid deprotonation and oxidation by net hydride transfer occurs. Together, the results suggest the selectivity and broad substrate scope unique to O tmpd are best attributed to the combination of ligand flexibility, limited steric demands, and ligand oxidative stability. In keeping with the absence of rate limiting C-H scission, O tmpd exhibits a marked insensitivity to the strength of the substrate Cα-H bond, readily oxidizing benzyl alcohol and 1 octanol at near identical rates.

    View details for DOI 10.1016/j.ica.2018.11.027

    View details for PubMedID 31485082

    View details for PubMedCentralID PMC6724545

  • Exclusive imidazole ligation to CuO2 and CuIIICuO2 cores. Chemical communications (Cambridge, England) Keown, W., Large, T. A., Chiang, L., Wasinger, E. C., Stack, T. D. 2019

    Abstract

    We disclose herein the synthesis and characterization of L2Cu(iii)2O2 and L3Cu(iii)Cu(ii)2O2 complexes with nitrogen ligation exclusively from imidazoles for the first time. Their accessibility by direct oxygenation of a L-Cu(i) precursor and the resulting Cu(iii) formation inform on the kinetic accessibility and thermodynamic superiority of imidazole in stabilizing Cu(iii).

    View details for DOI 10.1039/c9cc02982f

    View details for PubMedID 31173011