The PRC-barrel: a widespread, conserved domain shared by photosynthetic reaction center subunits and proteins of RNA metabolism

The PRC-H β-barrel domain, a distinct cytoplasmic β-barrel domain whose fold has no close structural relationship to any other well known β-barrel domain, is the prototype of a novel superfamily of protein domains approximately 80 residues long. This domian is a widespread, ancient domain that appears to have been recruited to a variety of biological systems, ranging from RNA processing to photosynthesis.