Year-end Sale % OFF 
Abstract
PREP1 and PBX1 are homeodomain (HD) transcription factors that play crucial roles in embryonic development. Here, we present the first biophysical characterization of a PREP1 HD, and the NMR spectroscopic study of its DNA binding pocket. The data show that residues flanking the HD participate in DNA binding. The kinetic parameters for DNA binding of individual PREP1 and PBX1 HDs, and of their combination, show that isolated PREP1 and PBX1 HDs bind to DNA in a cooperative manner. A novel PREP1 motif, flanking the HD at the C-terminus, is required for cooperativity.
Highlights
As shown in many crystal and NMR structures[3,21,26], HD transcription factors contact DNA recognition sites through residues N51 and R55 in the third α-helix of the HD
Our data demonstrate that PBX1:PREP1 HDs cooperate on DNA binding
The C-terminal tail seems to contribute more significantly than the N-terminal tail, as the KD of PREP1hd-C (15.5 μM) is the same as that of PREP1HD (Table 1), whereas the KD of PREP1hd-N (23.7 μM) is reduced. These results suggest that the presence of PREP1 HD C-terminal extension residues is important for high affinity DNA binding
Summary
As shown in many crystal and NMR structures[3,21,26], HD transcription factors contact DNA recognition sites through residues N51 and R55 in the third α-helix of the HD. N51 mediates the bidentate hydrogen bond with an adenine base, while R55 forms two hydrogen bonds with a guanine and both contact DNA in the major groove[3]. That does not participate in DNA binding[27] It was observed for HOX proteins that even non-specific interactions with DNA can increase DNA-binding affinity[21]. PBX1 and PREP1 can bind DNA independently when uncoupled, but require a specific functional interaction at the HD level for high affinity, thereby being sensitive to the DNA-binding state of the partner[19]. We have explored the functional and physical-chemical properties of isolated HDs and compared the affinity to DNA of different PREP1 HD constructs. The DNA interactions of two PREP1 HD constructs that differ in the amino- and carboxy-terminal extensions were studied by NMR spectroscopy. Our data demonstrate that PBX1:PREP1 HDs cooperate on DNA binding
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
