This is a large family of uncharacterised proteins found in all domains of life. The structure shows a novel fold with three beta sheets. A dimeric form is found in the crystal structure. It was suggested that the cleft in between the two monomers might bing nucleic acid [1].

1: X-ray crystal structure of MTH938 from Methanobacterium thermoautotrophicum at 2.2 A resolution reveals a novel tertiary protein fold. Das K, Xiao R, Wahlberg E, Hsu F, Arrowsmith CH, Montelione GT, Arnold E; Proteins 2001;45:486-488. PMID:11746696