RNA polymerase subunit H features a beta-ribbon motif within a novel fold that is present in archaea and eukaryotes.
Thiru, A., Hodach, M., Eloranta, J.J., Kostourou, V., Weinzierl, R.O., Matthews, S.(1999) J Mol Biol 287: 753-760
- PubMed: 10191143 
- DOI: https://doi.org/10.1006/jmbi.1999.2638
- Primary Citation of Related Structures:  
1HMJ - PubMed Abstract: 
The archaeal H and eukaryotic RPB5 RNA polymerase subunits are highly homologous and are likely to play a fundamental role in transcription that extends from archaea to humans. We report the structure of subunit H, in solution, from the archaeon Methanococcus jannaschii using multidimensional nuclear magnetic resonance. The structure reveals a novel fold containing a four-stranded mixed beta sheet that is flanked on one side by three short helices. The dominant feature is beta-ribbon motif, which presents a hydrophobic, basic surface, and defines a general RNA polymerase architectural scaffold.
Organizational Affiliation: 
Department of Biochemistry, Imperial College of Science Technology and Medicine, Exhibition Road, London, South Kensington, SW7 2AY, UK.