Members of this family of prokaryotic proteins adopt a fold consisting of one alpha-helix and four beta-strands. Their function has not, as yet, been elucidated [1].

1: Crystal structure of the hypothetical protein TTHA1013 from Thermus thermophilus HB8. Hattori M, Mizohata E, Manzoku M, Bessho Y, Murayama K, Terada T, Kuramitsu S, Shirouzu M, Yokoyama S; Proteins. 2005;61:1117-1120. PMID:16250002