Chemical-genetic interactions with the proline analog L-azetidine-2-carboxylic acid inSaccharomyces cerevisiae

Abstract

Non-proteinogenic amino acids, such as the proline analog L-azetidine-2-carboxylic acid (AZC), are detrimental to cells because they are mis-incorporated into proteins and lead to proteotoxic stress. Our goal was to identify genes that show chemical-genetic interactions with AZC in Saccharomyces cerevisiae and thus also potentially define the pathways cells use to cope with amino acid mis-incorporation. Screening the yeast deletion and temperature sensitive collections, we found 72 alleles with negative synthetic interactions with AZC treatment and 12 alleles that suppress AZC toxicity. Many of the genes with negative synthetic interactions are involved in protein quality control pathways through the proteasome. Genes involved in actin cytoskeleton organization and endocytosis also had negative synthetic interactions with AZC. Related to this, the number of actin patches per cell increases upon AZC treatment. Many of the same cellular processes were identified to have interactions with proteotoxic stress caused by two other amino acid analogs, canavanine and thialysine, or a mistranslating tRNA variant that mis-incorporates serine at proline codons. Alleles that suppressed AZC-induced toxicity functioned through the amino acid sensing TOR pathway or controlled amino acid permeases required for AZC uptake.

The amino acid substitution affects cellular response to mistranslation

“…Analysis of the biological function of the genes displaying negative genetic interactions with the mistranslating tRNA variants revealed both distinct and common processes. Not surprisingly, many of the processes were also identified in chemical-genetic screens with amino acid analogs that are incorporated into protein (Berg et al 2020). As mentioned above, the most notable difference in the genetic interaction patterns between the two tRNAs is the increased number with tRNA Ser UCU, G26A .…”

Desulfurized and Hydrogenated Crude Sulfate Turpentine (HCST): A Biofuel Derived from a Waste of the Pulp and Paper Industries

“…As a result of the sodium sulfide present in the white liquor, the CST leaves the digester with a sulfur content higher than pine resin turpentine . While the latter has a sulfur content between 40 and 50 mg/kg, the CST obtained from the Kraft process varies between 200 and 20000 mg/kg, depending on the type of wood used and the type of Kraft factory . The Kraft process involves the generation of a large amount of CST, which could be used as biofuel once the sulfur is removed and its combustion properties are improved.…”