Structural basis of terephthalate recognition by solute binding protein TphC

From Springer Nature via Jisc Publications RouterHistory: received 2021-03-24, accepted 2021-10-06, registration 2021-10-12, pub-electronic 2021-10-29, online 2021-10-29, collection 2021-12Publication status: PublishedFunder: Commonwealth Scholarship Commission (CSC); doi: https://doi.org/10.13039/501100000867; Grant(s): INCN-2018-57Funder: RCUK | Engineering and Physical Sciences Research Council (EPSRC); doi: https://doi.org/10.13039/501100000266; Grant(s): EP/M013219/1, EP/023755/1Funder: RCUK | Biotechnology and Biological Sciences Research Council (BBSRC); doi: https://doi.org/10.13039/501100000268; Grant(s): BB/M011208/1, BB/M011208/1, BB/P01738X/1Abstract: Biological degradation of Polyethylene terephthalate (PET) plastic and assimilation of the corresponding monomers ethylene glycol and terephthalate (TPA) into central metabolism offers an attractive route for bio-based molecular recycling and bioremediation applications. A key step is the cellular uptake of the non-permeable TPA into bacterial cells which has been shown to be dependent upon the presence of the key tphC gene. However, little is known from a biochemical and structural perspective about the encoded solute binding protein, TphC. Here, we report the biochemical and structural characterisation of TphC in both open and TPA-bound closed conformations. This analysis demonstrates the narrow ligand specificity of TphC towards aromatic para-substituted dicarboxylates, such as TPA and closely related analogues. Further phylogenetic and genomic context analysis of the tph genes reveals homologous operons as a genetic resource for future biotechnological and metabolic engineering efforts towards circular plastic bio-economy solutions

The Merger of Aryl Radical-Mediated Halogen-Atom Transfer (XAT) and Copper Catalysis for the Modular Cross-Coupling-Type Functionalization of Alkyl Iodides

Here, we report a toolbox strategy to cross-couple unactivated secondary alkyl iodides with various N-, O-, and C-based nucleophiles. This strategy harnesses the ability of photoredox-generated phenyl radicals to mediate halogen-atom transfer (XAT) and convert alkyl iodides into the corresponding radicals. These species engage in a second catalytic cycle, mediated by copper, which enables C–N/O/C bond formation with the various nucleophiles

Radical hydroxymethylation of alkyl iodides using formaldehyde as a C1 synthon.

From PubMed via Jisc Publications RouterHistory: received 2021-06-07, accepted 2021-07-06Publication status: epublishRadical hydroxymethylation using formaldehyde as a C1 synthon is challenging due to the reversible and endothermic nature of the addition process. Here we report a strategy that couples alkyl iodide building blocks with formaldehyde through the use of photocatalysis and a phosphine additive. Halogen-atom transfer (XAT) from α-aminoalkyl radicals is leveraged to convert the iodide into the corresponding open-shell species, while its following addition to formaldehyde is rendered irreversible by trapping the transient O-radical with PPh . This event delivers a phosphoranyl radical that re-generates the alkyl radical and provides the hydroxymethylated product. [Abstract copyright: This journal is © The Royal Society of Chemistry.

Structural basis of terephthalate recognition by solute binding protein TphC

The presence of the gene encoding the solute binding protein TphC has been shown to permit the uptake of terephthalate (TPA), which is the breakdown product of Polyethylene terephthalate (PET) plastic. Here the authors present a structural characterization of TphC in both open and TPA-bound closed conformations