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Biology subjects

Sone, K.

Publications and source records attributed to Sone, K..

3 recordsLinked to original sources

Reprogramming protein interfaces between adenylation and carrier protein domains in nonribosomal peptide synthetases

Nonribosomal peptide synthetases (NRPSs) assemble structurally diverse bioactive natural products through selective communication between adenylation (A) and carrier protein (CP) domains. Although rational rewiring of these protein-protein interactions could enable customized NRPS design, this remains challenging due to the dynamic nature of protein interfaces. Here we show that structure-guided interface reprogramming enables productive non-cognate A- CP pairings across enterobactin, vibriobactin, pyochelin, and vicenistatin biosynthetic systems. Engineered interactions between the A domains EntE, VibE, or PchD and the non-cognate CPs VinL or EntB were validated by biochemical, kinetic, and structural analyses. Reconstituted pathways containing engineered VibE, EntB, and EntF restored enterobactin production and increased yield to 2.2-fold that of the native EntE-EntB-EntF system. Interface-engineered PchD also enhanced production of a non-native salicylic acid-norspermidine conjugate. An X-ray structure and molecular dynamics simulations of an engineered non-cognate A-CP complex reveal recognition principles for programmable NRPS interface design.

biochemistry↗

Crystal structure of plant γ-glutamyl peptidase 1 with dual roles in sulfur metabolism and implications for oxidative stress regulation

{gamma}-Glutamyl peptidase 1 (GGP1) plays a dual role in primary and secondary sulfur metabolism in Arabidopsis thaliana. During glutathione (GSH) turnover, GGP1 hydrolyzes the isopeptide bond of GSH to degrade the tripeptide into Glu and Cys-Gly. During glucosinolate and camalexin biosynthesis, GGP1 processes GSH conjugates, which have a large substituent at the thiol side chain, by hydrolyzing the same isopeptide bond of {gamma}-Glu. In the present study, we determined the crystal structures of the following GGP1 forms: ligand-free, Glu complex, covalent {gamma}-Glu intermediate, and disulfide-linked S-S inactive forms. The intermediate structure, in which {gamma}-Glu is covalently linked to the nucleophile C100, was trapped by mutating the catalytic His to Asn (H192N). In the Glu complex and {gamma}-Glu intermediate structures, Glu bound to the S1 subsite is extensively recognized by several hydrogen bonds. The substrate recognition of the Cys-Gly moiety at the S1 and S2 subsites was revealed by modeling GSH in the active site. Mutational analysis indicated that R206 plays an important role in substrate binding by forming a salt bridge with Gly at the S2 subsite. An open pocket is present beyond the thiol side chain of Cys in the S1 subsite, which contributed to the dual activity of GGP1 toward GSH and GSH conjugates. The S-S inactive structure was obtained by soaking GGP1 crystals in Cys-Gly, and the catalytic cysteine (C100) partially formed a disulfide bond with a neighboring C154 residue. The partial inactivation of GGP1 in the presence of a pro-oxidant (Cys-Gly) has revealed its possible role in oxidative stress regulation in Arabidopsis.

biochemistry↗

Identification of genes supporting cold resistance of mammalian cells: lessons from a hibernator

Susceptibility of human cells to cold stress restricts the use of therapeutic hypothermia and long-term preservation of organs at low temperatures. In contrast, cells of mammalian hibernators possess remarkable cold resistance, but little is known about the molecular mechanisms underlying this phenomenon. In this study, we conducted a gain-of-function screening of genes that confer cold resistance to cold-vulnerable human cells using a cDNA library constructed from the Syrian hamster, a mammalian hibernator, and identified Gpx4 as a potent suppressor of cold-induced cell death. Additionally, genetic or pharmacological inhibition of Gpx4 in a hamster cell line under prolonged cold culture led to cell death, which resembles ferroptosis characterized by accumulation of lipid peroxide and ferrous iron dependency. Genetic disruption of other ferroptosis-suppressing pathways, namely biopterin synthesis and mitochondrial or plasma membrane CoQ reduction pathways, accelerated cold-induced cell death under Gpx4 dysfunction. Collectively, ferroptosis-suppressing pathways protect the cells of a mammalian hibernator from cold-induced cell death and the augmentation of these pathways renders cold resistance to cells of non-hibernators, including humans.

cell biology↗