# Structure, Oligomerization, and Thermal Stability of a Recently Discovered Old Yellow Enzyme

## TL;DR

This paper studies a heat-stable enzyme from a non-extreme organism, revealing structural features that explain its unusual stability.

## Contribution

The paper identifies unique structural and biochemical features of FOYE that contribute to its thermal stability and oligomerization.

## Key findings

- FOYE forms a tetramer with unique interactions not seen in other homologs.
- High intramolecular hydrogen bonds are key to FOYE's thermal stability.
- Phylogenetic analysis shows FOYE clusters separately from other tetrameric homologs.

## Abstract

The Old Yellow Enzyme from Ferrovum sp. JA12 (FOYE) displays an unusual thermal stability for an enzyme isolated from a mesophilic organism. We determined the crystal structure of this enzyme and performed bioinformatic characterization to get insights into its thermal stability. The enzyme displays a tetrameric quaternary structure; however, unlike the other tetrameric homologs, it clusters in a separate phylogenetic group and possesses unique interactions that stabilize this oligomeric state. The thermal stability of this enzyme is mainly due to an unusually high number of intramolecular hydrogen bonds. Finally, this study provides a general analysis of the forces driving the oligomerization in Old Yellow Enzymes.