Modifying Post‐Translational Modifications: A Strategy Used by Archaea for Adapting to Changing Environments?

Abstract

In concert with the selective pressures affecting protein folding and function in the extreme environments in which they can exist, proteins in Archaea have evolved to present permanent molecular adaptations at the amino acid sequence level. Such adaptations may not, however, suffice when Archaea encounter transient changes in their surroundings. Post‐translational modifications offer a rapid and reversible layer of adaptation for proteins to cope with such situations. Here, it is proposed that Archaea further augment their ability to survive changing growth conditions by modifying the extent, position, and, where relevant, the composition of different post‐translational modifications, as a function of the environment. Support for this hypothesis comes from recent reports describing how patterns of protein glycosylation, methylation, and other post‐translational modifications of archaeal proteins are altered in response to environmental change. Indeed, adjusting post‐translational modifications as a means to cope with environmental variability may also hold true beyond the Archaea.

Self-assembly of emulsion droplets through programmable folding

“…Our minimal model system exhibits many of the phenomena nominally associated with protein folding. Foldamers comprised of droplets with two or three flavors have the properties of uniqueness [38], robustness [39], and kinetic accessibility in a funnel landscape [33]. The core collapse folding mechanism resembles the hydrophobic collapse in proteins [40,41], while that of geometric frustration has been proposed as a design principle in the assembly of peptides [42].…”

N‐glycosylation in Archaea—New roles for an ancient posttranslational modification

“…Although we now know that Archaea reside across a wide range of environments, these microorganisms remain best known as extremophiles, namely creatures able to thrive in some of the harshest environments on Earth, including those characterized by extremes of temperature, salinity and pH (Baker et al ., 2020). Posttranslational modifications, such as protein glycosylation, have long been assigned importance in the ability of the proteins of extremophilic Archaea to remain folded, and hence functional, in the face of such physical challenges (Mengele and Sumper, 1992; Arbiv et al ., 2013; Tamir and Eichler, 2017; Eichler, 2020). More recent studies have, however, expanded the concept of how N‐glycosylation can be exploited by proteins exposed to extreme conditions.…”