Characterization of a novel cold-adapted intracellular serine protease from the extremophile Planococcus halocryophilus Or1

Abstract

The enzymes of microorganisms that live in cold environments must be able to function at ambient temperatures. Cold-adapted enzymes generally have less ordered structures that convey a higher catalytic rate, but at the cost of lower thermodynamic stability. In this study, we characterized P355, a novel intracellular subtilisin protease (ISP) derived from the genome of Planococcus halocryophilus Or1, which is a bacterium metabolically active down to −25°C. P355′s stability and activity at varying pH values, temperatures, and salt concentrations, as well as its temperature-dependent kinetics, were determined and compared to an uncharacterized thermophilic ISP (T0099) from Parageobacillus thermoglucosidasius, a previously characterized ISP (T0034) from Planococcus sp. AW02J18, and Subtilisin Carlsberg (SC). The results showed that P355 was the most heat-labile of these enzymes, closely followed by T0034. P355 and T0034 exhibited catalytic constants (kcat) that were much higher than those of T0099 and SC. Thus, both P355 and T0034 demonstrate the characteristics of the stability-activity trade-off that has been widely observed in cold-adapted proteases.

Metagenomic exploration of cold‐active enzymes for detergent applications: Characterization of a novel, cold‐active and alkali‐stable GH8 endoglucanase from ikaite columns in SW Greenland

“…The polar regions, characterized by a harsh climate and pristine ecosystems, have become the focus of attention as a source of cold‐active microorganisms and their potential genetic resources. Especially the marine and aquatic environments (including permafrost brine channels) have proven to be reservoirs of rich microbial communities, with expected enzymatic activities tailored to survive and retain cellular functions at low temperatures (Cristóbal et al., 2011 ; De Santi et al., 2016 ; Huston et al., 2000 ; Mykytczuk et al., 2013 ; Rasmussen et al., 2023 ; Schmidt et al., 2007 ; Söderberg et al., 2019 ; Srinivas et al., 2009 ). One polar environment of particular interest, regarding discovery of enzymes relevant for detergent applications, is ikaite columns in the Ikka Fjord, SW Greenland (Seaman et al., 2022 ).…”