NMR Study of the Interaction of the HU Protein from Bacillus Stearothermophilus with DNA

✍ Scribed by Hans Vis; Olga Vageli; Jord Nagel; Constantin E. Vorgias; Keith S. Wilson; Robert Kaptein; Rolf Boelens

• Publisher: John Wiley and Sons
• Year: 1996
• Tongue: English
• Weight: 581 KB
• Volume: 34
• Category: Article
• ISSN: 0749-1581
• DOI: 10.1002/(sici)1097-458x(199612)34:13<s81::aid-omr67>3.0.co;2-7

✦ Synopsis

DNA binding of the 19.5 kDa protein HU from Bacillus steurothermophilus (HUBst) with several non-specific double-stranded DNA oligomers was studied using NMR techniques. Photochemically induced nuclear polarization (photo-CIDNP) measurements on a mutant HUBst (M69Y; V76Y) show that Y69 in the tip of the /I-hairpin arm is involved in DNA interaction. Changes in "N and 'HN chemical shifts upon titrating DNA are greatest for the residues in the &hairpin arm and for the residues in the second half of the third a-helix. The changes in the flexible arms can be interpreted as being due to the formation of more rigid secondary structure upon DNA binding. Backbone and side-chain dynamics of HUBst were investigated using heteronuclear 15N-'HN NOE, "N Ti and Tip data for free and complexed HUBst. These measurements show that the mobility of the flexible arms reduces in the protei*DNA complex. The results demonstrate that the /?-hairpin arms and the C-terminal a-helix of HUBst are involved in DNA binding.