A group of hypothetical eukaryotic proteins, characterized by the presence of an adenine nucleotide alpha hydrolase (AANH)-like domain located N-terminal to two distinctly different YjgF-YER057c-UK114-like domains. This CD contains the first of these domains. The YjgF-YER057c-UK114 protein family is a large family of proteins present in bacteria, archaea, and eukaryotes with no definitive function. The conserved domain is similar in structure to chorismate mutase but there is no sequence similarity and no functional connection. Members of this family have been implicated in isoleucine (Yeo7, Ibm1, aldR) and purine (YjgF) biosynthesis, as well as threonine anaerobic degradation (tdcF) and mitochondrial DNA maintenance (Ibm1). This domain homotrimerizes forming a distinct intersubunit cavity that may serve as a small molecule binding site.