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PDBsum entry 1fip
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DNA binding protein
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PDB id
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1fip
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Contents |
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* Residue conservation analysis
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References listed in PDB file
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Key reference
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Title
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The structure of fis mutant pro61ala illustrates that the kink within the long alpha-Helix is not due to the presence of the proline residue.
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Authors
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H.S.Yuan,
S.S.Wang,
W.Z.Yang,
S.E.Finkel,
R.C.Johnson.
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Ref.
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J Biol Chem, 1994,
269,
28947-28954.
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PubMed id
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Abstract
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The influence of proline on bending of the alpha-helix was investigated by
replacement of the proline residue located in the middle of the long alpha-helix
of the Fis protein with alanine, serine, or leucine. Each of the three
substitutions folded into a stable protein with the same or higher melting
points than the wild-type, but only Pro61Ala was functionally active in
stimulating Hin-mediated DNA inversion. Pro61Ala formed crystals that were
isomorphous with the wild-type protein allowing the structure to be determined
at 1.9-A resolution by x-ray diffraction methods. The structure of the Pro61Ala
mutant is almost identical to the wild-type protein, consistent with its near
wild-type activity. One of the alpha-helices, the B-helix, is kinked in the
wild-type Fis protein by 20 degrees which was previously assumed to be caused
solely by the presence of proline 61 in the center of the helix. However, the
B-helix is still kinked by 16 degrees when proline 61 is replaced by alanine.
Local peptide backbone movement around residue 57 adjusts the geometry of the
helix to accommodate the new main chain hydrogen bond between the -CO group in
Glu57 and the -NH group in Ala61. Thus, the kink of the alpha-helix in Pro61Ala
does not require the presence of proline.
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