| Primary Identifier | IPR005231 | Type | Family |
| Short Name | NAC_arc |
| description | Eukaryotic NAC, an abundant heterodimer composed of two homologous subunits, reversibly binds eukaryotic ribosomes and is located in direct proximity to nascent polypeptides as they emerge from the ribosome []. Despite being implicated in diverse cellular functions, its role in vivois still not completely understood. It is thought that NAC may function as a shield protecting the nascent chain from inappropriate interactions with cytosolic factors, and could regulate further translation of the polypeptide through its interaction with the ribosome.Archaeal NAC is a homodimer which appears to be functionally analogous to the eukaryotic form, associating with ribosomes and contacting the nascent polypeptide chain emerging on the ribosome []. It has two domains; the NAC domain, which it shares with eukaryotic NAC, and a C-terminal UBA domain also found on the alpha, but not beta, subunit of eukaryotic NAC. The NAC domain forms a six-stranded β-barrel structure which shows some similarities to the OB fold. This domain appears to be responsible for dimerisation, nucleic acid binding, and nascent polypeptide binding. The UBA domain is typical of ubiquitin or polyubquitin-binding proteins; its physiological role is unclear but it was suggested that it may compete with the proteosome for ubiquitin, thus inhibiting ubiquitin-mediated protein degradation. |
