This family consists of bacterial proteins related to YacP. This family is uncharacterised functionally, but it has been suggested that these proteins are nucleases due to them containing a NYN domain. NYN (for N4BP1, YacP-like Nuclease) domains were discovered by Anantharaman and Aravind [1]. Based on gene neighborhoods it was suggested that the bacterial YacP proteins interact with the Ribonuclease III and TrmH methylase in a processome complex that catalyzes the maturation of rRNA and tRNA [1].

1: The NYN Domains: Novel Predicted RNAses with a PIN Domain-Like Fold. Anantharaman V, Aravind L; RNA Biol. 2006; [Epub ahead of print] PMID:17114934