Arabidopsis heat stress-induced proteins are enriched in electrostatically charged amino acids and intrinsically disordered regions. Arabidopsis heat stress-induced proteins are enriched in electrostatically charged amino acids and intrinsically disordered regions

Comparison of the proteins of thermophilic, mesophilic and psychrophilic prokaryotes has revealed a number of features characteristic to proteins adapted to high temperatures, which increase their thermostability. These characteristics include an excess of disulfide bonds, salt bridges, hydrogen bonds, and hydrophobic interactions, and a depletion in intrinsically disordered regions. It is unclear, however, whether such differences can also be observed when comparing proteins that are adapted to temperatures that are more subtly different. When an organism is exposed to high temperatures, a subset of its proteins are overexpressed (heat-induced proteins), whereas others are repressed (heat-repressed proteins). Here, we determine the expression levels of all Arabidopsis thaliana genes at 22 and 37°C, and compare the amino acid compositions and levels of intrinsic disorder of heat-induced and heat-repressed proteins. We show that heat-induced proteins are enriched in electrostatically charged amino acids and depleted in polar amino acids, mirroring thermopile proteins. However, in contrast with thermophile proteins, heat-repressed proteins are enriched in intrinsically disordered regions and depleted in hydrophobic amino acids. These results indicate that temperature adaptation at the level of amino acid composition and intrinsic disorder can be observed not only in proteins of thermophilic organisms, but also in eukaryotic heat-induced proteins; however, the underlying adaptation pathways are similar but not exactly the same. Overall design: Col-0 seedlings were grown in MS plates under darkness conditions . There were keep at 22°C for 72 hours, at this moment plates were either kept at 22 ºC or transferred to 37º C, also one control sample with four replicates that we call time 0h was collected. Seedlings were harvested after 24 hours with four biological replicates. All samples were Cy3 labelled.