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PDBsum entry 1q04
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Hormone/growth factor
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PDB id
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1q04
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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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Sequence swapping does not result in conformation swapping for the beta4/beta5 and beta8/beta9 beta-Hairpin turns in human acidic fibroblast growth factor.
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Authors
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J.Kim,
J.Lee,
S.R.Brych,
T.M.Logan,
M.Blaber.
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Ref.
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Protein Sci, 2005,
14,
351-359.
[DOI no: ]
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PubMed id
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Abstract
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The beta-turn is the most common type of nonrepetitive structure in globular
proteins, comprising ~25% of all residues; however, a detailed understanding of
effects of specific residues upon beta-turn stability and conformation is
lacking. Human acidic fibroblast growth factor (FGF-1) is a member of the
beta-trefoil superfold and contains a total of five beta-hairpin structures
(antiparallel beta-sheets connected by a reverse turn). beta-Turns related by
the characteristic threefold structural symmetry of this superfold exhibit
different primary structures, and in some cases, different secondary structures.
As such, they represent a useful system with which to study the role that turn
sequences play in determining structure, stability, and folding of the protein.
Two turns related by the threefold structural symmetry, the beta4/beta5 and
beta8/beta9 turns, were subjected to both sequence-swapping and poly-glycine
substitution mutations, and the effects upon stability, folding, and structure
were investigated. In the wild-type protein these turns are of identical length,
but exhibit different conformations. These conformations were observed to be
retained during sequence-swapping and glycine substitution mutagenesis. The
results indicate that the beta-turn structure at these positions is not
determined by the turn sequence. Structural analysis suggests that residues
flanking the turn are a primary structural determinant of the conformation
within the turn.
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Figure 4.
Figure 4. Relaxed stereo diagram illustrating an overlay of
the  4/ 5 turn regions
for WT* (CPK coloring), V51N (red), S50G/V51G (magenta), and
S50E/V51N (green) mutants. None of the sequence substitution, or
polyglycine substitutions, within this turn affected the
structure of the turn.
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Figure 5.
Figure 5. Relaxed stereo diagram of a close-up of an
overlay of the 4/ 5 (light gray)
and 8/ 9 (dark gray)
turns showing the local side chain interactions.
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The above figures are
reprinted
by permission from the Protein Society:
Protein Sci
(2005,
14,
351-359)
copyright 2005.
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