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PDBsum entry 6tob
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DNA binding protein
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PDB id
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6tob
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References listed in PDB file
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Key reference
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Title
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Structural and DNA binding properties of mycobacterial integration host factor mihf.
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Authors
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N.T.Odermatt,
M.Lelli,
T.Herrmann,
L.A.Abriata,
A.Japaridze,
H.Voilquin,
R.Singh,
J.Piton,
L.Emsley,
G.Dietler,
S.T.Cole.
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Ref.
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J Struct Biol, 2020,
209,
107434.
[DOI no: ]
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PubMed id
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Abstract
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In bacteria, nucleoid associated proteins (NAPs) take part in active chromosome
organization by supercoil management, three-dimensional DNA looping and direct
transcriptional control. Mycobacterial integration host factor (mIHF, rv1388) is
a NAP restricted to Actinobacteria and essential for survival of the human
pathogen Mycobacterium tuberculosis. We show in vitro that DNA binding by mIHF
strongly stabilizes the protein and increases its melting temperature. The
structure obtained by Nuclear Magnetic Resonance (NMR) spectroscopy
characterizes mIHF as a globular protein with a protruding alpha helix and a
disordered N-terminus, similar to Streptomyces coelicolor IHF (sIHF). NMR
revealed no residues of high flexibility, suggesting that mIHF is a rigid
protein overall that does not undergo structural rearrangements. We show that
mIHF only binds to double stranded DNA in solution, through two DNA binding
sites (DBSs) similar to those identified in the X-ray structure of sIHF.
According to Atomic Force Microscopy, mIHF is able to introduce left-handed
loops of ca. 100 nm size (~300 bp) in supercoiled cosmids, thereby unwinding
and relaxing the DNA.
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