<p> This entry describes lysine-2,3-aminomutase as found along with beta-lysine acetyltransferase in a two-enzyme pathway for making the compatible solute N-epsilon-acetyl-beta-lysine. This compatible solute, or osmolyte, is known to protect a number of methanogenic archaea against salt stress. The trusted cutoff distinguishes a tight clade with essentially full-length homology from additional homologs that are shorter or highly diverged in the C-terminal region. All members of this family have the radical SAM motif CXXXCXXC, while some but not all have a second copy of the motif in the C-terminal region. </p>