A critical role in structure-specific DNA binding for the acetylatable lysine residues in HMGB1.
The structure-specific DNA-binding protein HMGB1 (high-mobility group protein B1) which comprises two tandem HMG boxes (A and B) and an acidic C-terminal tail, is acetylated in vivo at Lys(2) and Lys(11) in the A box. Mutation to alanine of both residues in the isolated A domain, which has a strong preference for pre-bent DNA, abolishes binding to four-way junctions and 88 bp DNA minicircles. The same mutations in full-length HMGB1 also abolish its binding to four-way junctions, and binding to minicircles is substantially impaired. In contrast, when the acidic tail is absent (AB di-domain) there is little effect of the double mutation on four-way junction binding, although binding to minicircles is reduced approximately 15-fold. Therefore it appears that in AB the B domain is able to substitute for the non-functional A domain, whereas in full-length HMGB1 the B domain is masked by the acidic tail. In no case does single substitution of Lys(2) or Lys(11) abolish DNA binding. The double mutation does not significantly perturb the structure of the A domain. We conclude that Lys(2) and Lys(11) are critical for binding of the isolated A domain and HMGB1 to distorted DNA substrates.
Assenberg
René
R
Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA, UK.
Webb
Michelle
M
Connolly
Edward
E
Stott
Katherine
K
Watson
Matthew
M
Hobbs
Josie
J
Thomas
Jean O
JO
D000107:Acetylation; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D050882:CREB-Binding Protein / Q000378:metabolism; D002942:Circular Dichroism; D004247:DNA / Q000737:chemistry* / Q000378:metabolism*; D024243:HMGB1 Protein / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D008239:Lysine / Q000235:genetics / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D019906:Nuclear Magnetic Resonance, Biomolecular; D009690:Nucleic Acid Conformation; D011485:Protein Binding; D017434:Protein Structure, Tertiary
D024243:HMGB1 Protein; D004247:DNA; D050882:CREB-Binding Protein; D008239:Lysine