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Crystal structure of the transcription factor sc‐mtTFB offers insights into mitochondrial transcription
Author(s) -
Schubot Florian D.,
Chen ChunJung,
Rose John P.,
Dailey Tamara A.,
Dailey Harry A.,
Wang BiCheng
Publication year - 2001
Publication title -
protein science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.353
H-Index - 175
eISSN - 1469-896X
pISSN - 0961-8368
DOI - 10.1110/ps.11201
Subject(s) - transcription (linguistics) , biology , rna polymerase , transcription factor ii f , rna polymerase ii , microbiology and biotechnology , promoter , general transcription factor , polymerase , binding site , rna , genetics , dna , gene , gene expression , philosophy , linguistics
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 Å resolution. The protein consists of two domains, an N‐terminal α/β‐domain and a smaller domain made up of four α‐helices. Contrary to previous predictions, sc‐mtTFB does not resemble Escherichia coli σ‐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.