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PDBsum entry 2w25
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Transcription
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PDB id
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2w25
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References listed in PDB file
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Key reference
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Title
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Ligand-Induced structural transitions, Mutational analysis, And 'Open' Quaternary structure of the m. Tuberculosis feast/famine regulatory protein (rv3291c).
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Authors
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T.Shrivastava,
A.Dey,
R.Ramachandran.
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Ref.
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J Mol Biol, 2009,
392,
1007-1019.
[DOI no: ]
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PubMed id
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Abstract
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Rv3291c is a member of the feast/famine regulatory protein family that is known
to form stable protein-DNA complexes. We report a specific oligomeric transition
between hexadecameric and octameric/lower-order oligomers in the presence of Phe
that supports an effector-mediated model for the disassembly of a
nucleosome-like particle. We had generated two mutants, Gly102Thr and Glu104Ala,
which are part of the essential 100-106 effector-binding loop. The Gly102Thr
mutant adopts an unusual 'open' quaternary structure and offers interesting
functional insights co-related to the binding of an effector. This is similar to
the previously reported Escherichia coli Lrp co-crystallized in the presence of
DNA where the interactions of the substrate with the N-terminal DNA binding
domain presumably lead to symmetry deviations to the oligomeric association. The
present structure represents a direct evidence to support that changes made to
the effector-binding domain at the C-terminus also result in a functionally
relevant quaternary structural change. Conversely, the Glu104Ala mutant retains
the closed quaternary association observed in the native protein and reveals
nonsymmetrical interaction effects in the two subunits of the dimer. We also
report that the native protein unexpectedly binds Lys but does not recognize Arg
and offer a structural explanation for it. Error-scaled difference distance
matrix analysis suggests that the protein has a relatively flexible core that is
presumably needed to mediate the structural changes necessary for the protein's
regulatory functions.
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Figure 3.
Fig. 3. Quaternary associations from the crystal structures.
(a) Gly102Thr, (b) Glu104Ala, and (c) E. coli Lrp (PDB ID: 2GQQ).
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Figure 6.
Fig. 6. Interactions of Lys in its complex with MtbLrp. The
protein is shown in cartoon representation. Hydrogen bonds are
indicated by broken lines. Selected binding site residues are
labeled and plotted in stick representation. Red spheres
indicate water molecules.
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The above figures are
reprinted
by permission from Elsevier:
J Mol Biol
(2009,
392,
1007-1019)
copyright 2009.
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