MJ0109 is an enzyme that is both an inositol monophosphatase and the 'missing' archaeal fructose-1,6-bisphosphatase.
Stec, B., Yang, H., Johnson, K.A., Chen, L., Roberts, M.F.(2000) Nat Struct Biol 7: 1046-1050
- PubMed: 11062561 
- DOI: 10.1038/80968
- Primary Citation of Related Structures:  
1DK4 - PubMed Abstract: 
In sequenced genomes, protein coding regions with unassigned function constitute between 10 and 50% of all open reading frames. Often key enzymes cannot be identified using sequence homology searches. For example, despite the fact that methanogens have an apparently functional gluconeogenesis pathway, standard tools have been unable to identify a fructose-1,6-bisphosphatase (FBPase) gene in the sequenced Methanoccocus jannaschii genome ...