Download MendeleyCrystal structure of the transcription factor sc-mtTFB offers insights into mitochondrial transcription.
Schubot, F.D., Chen, C.J., Rose, J.P., Dailey, T.A., Dailey, H.A., Wang, B.C.(2001) Protein Sci 10: 1980-1988
- PubMed: 11567089
- DOI: https://doi.org/10.1110/ps.11201
- Primary Citation of Related Structures:
1I4W - PubMed Abstract:
Although it is commonly accepted that binding of mitochondrial transcription factor sc-mtTFB to the mitochondrial RNA polymerase is required for specific transcription initiation in Saccharomyces cerevisiae, its precise role has remained undefined. In the present work, the crystal structure of sc-mtTFB has been determined to 2.6 A resolution. The protein consists of two domains, an N-terminal alpha/beta-domain and a smaller domain made up of four alpha-helices. Contrary to previous predictions, sc-mtTFB does not resemble Escherichia coli sigma-factors but rather is structurally homologous to rRNA methyltransferase ErmC'. This suggests that sc-mtTFB functions as an RNA-binding protein, an observation standing in contradiction to the existing model, which proposed a direct interaction of sc-mtTFB with the mitochondrial DNA promoter. Based on the structure, we propose that the promoter specificity region is located on the mitochondrial RNA polymerase and that binding of sc-mtTFB indirectly mediates interaction of the core enzyme with the promoter site.
Organizational Affiliation:
Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia 30602, USA.
