Eukaryotic N-Utilization Substance G (NusG) N-terminal (NGN) domain, including plant KTF1 (KOW domain-containing Transcription Factor 1)
The N-Utilization Substance G (NusG) protein and its eukaryotic homolog, Spt5, are involved in transcription elongation and termination. NusG contains an NGN domain at its N-terminus and Kyrpides Ouzounis and Woese (KOW) repeats at its C-terminus. Spt5 forms an Spt4-Spt5 complex that is an essential RNA polymerase II elongation factor. NusG was originally discovered as an N-dependent antitermination enhancing activity in Escherichia coli, and has a variety of functions such as its involvement in RNA polymerase elongation and Rho-termination in bacteria. Orthologs of the NusG gene exist in all bacteria, but their functions and requirements are different. Spt5-like is homologous to the Spt5 proteins present in all eukaryotes, which is unique as it encodes a protein with an additional long carboxy-terminal extension that contains WG/GW motifs. Spt5-like, or KTF1 (KOW domain-containing Transcription Factor 1), is a RNA-directed DNA methylation (RdDM) pathway effector in plants.
Structure:3H7H_B, Human Spt5 NGN domain and Spt4 form a heterodimer, contacts at 4.0 A - View structure with Cn3D
Comment:hSpt5-NGN is structurally similar to the NTD (N-terminal domain) of the bacterial transcription factor NusG
Comment:Eukaryotic Spt5 and Spt4 are involved in regulating the processivity of RNA polymerase II and play an essential role in eukaryotic transcriptional activation.
Comment:Eukaryotic Spt5 is comprised of an N-terminal acidic region followed by a NGN domain and several KOW repeats. The NGN domain of Spt5 forms a heterodimer with Spt4.
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