The sequence-specific high mobility group 1 box of TCF-1 adopts a predominantly alpha-helical conformation in solution.
The High Mobility Group (HMG) 1 box is a protein motif that mediates DNA binding in a novel family of transcription-regulating proteins. Several members of this family, including the lymphoid-specific proteins TCF-1 and LEF-1 and the mammalian sex-determining factor SRY, carry a single HMG box with affinity for the minor groove of the heptamer motif AACAAAG or variations thereof. To initiate studies on the structural characteristics of the TCF-1 HMG box, we have expressed the 87-amino acid HMG box in milligram quantities in Escherichia coli and purified the soluble peptide to > 95% homogeneity. The peptide bound DNA with the same specificity as the complete protein and was capable of inducing DNA bending. Circular dichroism (CD) analysis revealed the TCF-1 HMG box to adopt an approximately 60% alpha-helix/40% random coil conformation in solution. In the presence of an equimolar amount of double-stranded DNA containing the cognate motif, the CD spectrum changed significantly, implying the induction of a structural modification upon DNA/protein association.
van Houte
L
L
Department of Immunology, University Hospital, Utrecht, The Netherlands.
van Oers
A
A
van de Wetering
M
M
Dooijes
D
D
Kaptein
R
R
Clevers
H
H
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002942:Circular Dichroism; D003001:Cloning, Molecular; D004268:DNA-Binding Proteins; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000235:genetics; D006609:High Mobility Group Proteins / Q000737:chemistry* / Q000235:genetics; D051821:Lymphoid Enhancer-Binding Factor 1; D008322:Mammals; D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides; D010957:Plasmids; D016133:Polymerase Chain Reaction / Q000379:methods; D017433:Protein Structure, Secondary; D011994:Recombinant Proteins / Q000737:chemistry / Q000302:isolation & purification; D015183:Restriction Mapping; D012996:Solutions; D051822:T Cell Transcription Factor 1; D013601:T-Lymphocytes / Q000378:metabolism; D014157:Transcription Factors / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification
D004268:DNA-Binding Proteins; D006609:High Mobility Group Proteins; D051821:Lymphoid Enhancer-Binding Factor 1; D009838:Oligodeoxyribonucleotides; D011994:Recombinant Proteins; D012996:Solutions; D051822:T Cell Transcription Factor 1; D014157:Transcription Factors