NORMAL GENOMIC

• Worbs M, Bourenkov GP, Bartunik HD, Huber R, Wahl MC
• An extended RNA binding surface through arrayed S1 and KH domains in transcription factor NusA.
• Mol Cell. 2001; 7: 1177-89
• Display abstract

• The crystal structure of Thermotoga maritima NusA, a transcription factor involved in pausing, termination, and antitermination processes, reveals a four-domain, rod-shaped molecule. An N-terminal alpha/beta portion, a five-stranded beta-barrel (S1 domain), and two K-homology (KH) modules create a continuous spine of positive electrostatic potential, suitable for nonspecific mRNA attraction. Homology models suggest how, in addition, specific mRNA regulatory sequences can be recognized by the S1 and KH motifs. An arrangement of multiple S1 and KH domains mediated by highly conserved residues is seen, creating an extended RNA binding surface, a paradigm for other proteins with similar domain arrays. Structural and mutational analyses indicate that the motifs cooperate, modulating strength and specificity of RNA binding.

• Gibson TJ, Thompson JD, Heringa J
• 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.
• FEBS Lett. 1993; 324: 361-6
• Display abstract

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