InterPro domain: IPR013792

This superfamily represents an alpha/beta domain consisting of alternating beta-strands and alpha helices in two layer. This domain is found in RNA 3'-terminal phosphate cyclase (RPTC), where it occurs as a duplication of three repeats of this fold packed together around a pseudo three-fold axis [ 1 ]. RNA cyclases are a family of RNA-modifying enzymes that catalyse the ATP-dependent conversion of the 3'-phosphate to the 2',3'-cyclic phosphodiester at the end of RNA. These cyclases contain an insert alpha/beta domain with a thioredoxin topology ( IPR013791 ).

This domain is also found in enolpyruvate transferase, where it occurs as a duplication of six repeats of this fold organised into two RPTC-like domains [ 2 , 3 ]. Enolpyruvate transferase is the first enzyme in bacterial peptidoglycan biosynthesis, catalysing the transfer of enolpyruvate from phosphoenolpyruvate to UDP-N-acetyl-glucosamine.

1. Crystal structure of RNA 3'-terminal phosphate cyclase, a ubiquitous enzyme with unusual topology. Structure 8, 13-23
2. Stereochemical course of enzymatic enolpyruvyl transfer and catalytic conformation of the active site revealed by the crystal structure of the fluorinated analogue of the reaction tetrahedral intermediate bound to the active site of the C115A mutant of MurA. Biochemistry 37, 2572-7
3. Crystallization and preliminary X-ray crystallographic analysis of UDP-N-acetylglucosamine enolpyruvyl transferase from Haemophilus influenzae in complex with UDP-N-acetylglucosamine and fosfomycin. Mol. Cells 19, 398-401