Hypomutable regions of yeast TFIIB in a unigenic evolution test represent structural domains.
As genome sequences of many organisms - including humans - are being decoded, there is a great need for genetic tools to analyze newly discovered genes/proteins. A 'unigenic evolution' approach has been previously proposed for dissecting protein domains, which is based on the assumption that functionally important regions of a protein may tolerate missense mutations less well than other regions. We describe a unigenic evolution analysis of general transcription factor IIB (TFIIB) - a protein that is well characterized both structurally and functionally - to better understand the molecular basis of this genetic approach. The overall distribution profile of hypomutable regions within yeast TFIIB correlates extremely well with the known compact structural domains, suggesting that the unigenic evolution approach can help reveal structural properties of a protein. We further show that a small region located immediately carboxyl-terminal to the zinc ribbon motif is functionally important despite its strong hypermutability. Our study further demonstrates the usefulness of the unigenic evolution approach in dissecting protein domains, but suggests that the mutability of different regions of a protein in such a test is determined primarily by their structural properties.
Division of Developmental Biology, Children's Hospital Research Foundation, 3333 Burnet Avenue, Cincinnati, OH 45229, USA.
Xiao
X
Zeng
Dongyi
D
Zhang
Michael
M
Dorsey
Jun
J
Ma
D000595:Amino Acid Sequence; D001665:Binding Sites / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics; D019143:Evolution, Molecular; D005982:Glutathione Transferase / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D016296:Mutagenesis; D009154:Mutation; D011485:Protein Binding; D012319:RNA Polymerase II / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics*; D035581:Transcription Factor TFIIB / Q000235:genetics*
D011993:Recombinant Fusion Proteins; C073680:SUA7 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D035581:Transcription Factor TFIIB; D005982:Glutathione Transferase; D012319:RNA Polymerase II