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PDBsum entry 1hmf
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References listed in PDB file
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Key reference
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Title
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Structure of the hmg box motif in the b-Domain of hmg1.
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Authors
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H.M.Weir,
P.J.Kraulis,
C.S.Hill,
A.R.Raine,
E.D.Laue,
J.O.Thomas.
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Ref.
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Embo J, 1993,
12,
1311-1319.
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PubMed id
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Abstract
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The conserved, abundant chromosomal protein HMG1 consists of two highly
homologous, folded, basic DNA-binding domains, each of approximately 80 amino
acid residues, and an acidic C-terminal tail. Each folded domain represents an
'HMG box', a sequence motif recently recognized in certain sequence-specific
DNA-binding proteins and which also occurs in abundant HMG1-like proteins that
bind to DNA without sequence specificity. The HMG box is defined by a set of
highly conserved residues (most distinctively aromatic and basic) and appears to
define a novel DNA-binding structural motif. We have expressed the HMG box
region of the B-domain of rat HMG1 (residues 88-164 of the intact protein) in
Escherichia coli and we describe here the determination of its structure by 2D
1H-NMR spectroscopy. There are three alpha-helices (residues 13-29, 34-48 and
50-74), which together account for approximately 75% of the total residues and
contain many of the conserved basic and aromatic residues. Strikingly, the
molecule is L-shaped, the angle of approximately 80 degrees between the two arms
being defined by a cluster of conserved, predominantly aromatic, residues. The
distinctive shape of the HMG box motif, which is distinct from hitherto
characterized DNA-binding motifs, may be significant in relation to its
recognition of four-way DNA junctions.
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