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A novel matrix attachment region DNA binding motif identified using a random phage peptide library
B Wang1, L A Dickinson, E Koivunen
1Cancer Research Center, La Jolla Cancer Research Foundation, California 92037, USA.
The Journal of Biological Chemistry
|October 6, 1995
Summary
Researchers identified a key DNA-binding motif in the SATB1 protein using phage display. This nine-amino acid sequence is crucial for SATB1
Area of Science:
- Molecular Biology
- Genetics
Background:
- SATB1 is a nuclear matrix attachment DNA (MAR)-binding protein primarily found in thymocytes.
- SATB1 recognizes specific DNA contexts within MAR regions, characterized by base-unpairing propensity.
Purpose of the Study:
- To identify the specific DNA-binding motif of the SATB1 protein.
- To investigate the role of a identified peptide in SATB1's MAR binding activity.
Main Methods:
- Utilized a phage display library of random nonamer peptides to screen for MAR-binding peptides.
- Employed MAR-affinity chromatography for peptide selection.
- Performed site-directed mutagenesis and peptide replacement experiments in SATB1.
Main Results:
- A cyclic peptide (C1) with 50% sequence identity to SATB1 amino acids 355-363 was selected.
- Truncation or randomization of this SATB1 segment significantly reduced MAR binding (>80%).
- Replacing the SATB1 segment with C1 restored wild-type MAR binding activity and specificity.
Conclusions:
- A nine-amino acid sequence within SATB1 functions as a critical MAR-binding motif.
- Phage display is an effective method for rapidly identifying DNA-binding peptide motifs.