THE KH DOMAIN OCCURS IN A DIVERSE SET OF RNA-BINDING PROTEINS THAT INCLUDE THE ANTITERMINATOR NUSA AND IS PROBABLY INVOLVED IN BINDING TO NUCLEIC-ACID

New findings are presented for the approximately 50 residue KH motif, a domain recently discovered in RNA-binding proteins. The conserved se quence is approximately 10 residues larger than previously reported. P rofile searches have revealed new members of this family, including tw o, E coli NusA and human GAP-associated p62 phosphoprotein, for which RNA-binding data exists. A nusA homolog was detected in the RNA polyme rase gene complex of six archaebacterial species and may encode an ant iterminator. All KH-containing proteins are linked with RNA and the KH motif most probably functions as a nucleic acid binding domain.