The purpose of this project is to identify enzymes in prokaryotic cryophiles (“cold-loving”) with the aim of studying protein adaptations to lower temperatures and contrast them with enzymes from organisms adapted to higher temperatures. Data in the form of metatranscriptomes (metaT) from the 2021 SAS expedition to the Arctic is available as Illumina sequences. This will be processed by the nf-core/metatdenovo Nextflow pipeline (https://github.com/LNUc-EEMiS/metatdenovo/; under development) to produce a catalog of genes from prokaryotes adapted to Arctic waters. The gene catalog will then be screened for representative sequences of Adenylate Kinase homologues based on a HMMER analysis. Candidate genes will then be used for subsequent cloning, transformation into an expression system such as E. coli and used to express and purify the psychrophilic Adenylate Kinase protein. The purified protein will be used for functional assays with supporting structural studies using x-ray crystallography to allow for a biochemical characterization of the psychrophilic Adenylate Kinase. The gathered data will then be used for comparison to homologues of other organisms, such as human, bacterial or archaeal variants in order to identify essential structural principles necessary to enable enzyme catalysis across drastically differing conditions of life.