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PDBsum entry 1v8z
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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 crystal structure of the tryptophan synthase beta subunit from the hyperthermophile pyrococcus furiosus. Investigation of stabilization factors.
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Authors
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Y.Hioki,
K.Ogasahara,
S.J.Lee,
J.Ma,
M.Ishida,
Y.Yamagata,
Y.Matsuura,
M.Ota,
M.Ikeguchi,
S.Kuramitsu,
K.Yutani.
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Ref.
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Eur J Biochem, 2004,
271,
2624-2635.
[DOI no: ]
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PubMed id
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Abstract
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The structure of the tryptophan synthase beta2 subunit (Pfbeta2) from the
hyperthermophile, Pyrococcus furiosus, was determined by X-ray crystallographic
analysis at 2.2 A resolution, and its stability was examined by DSC. This is the
first report of the X-ray structure of the tryptophan synthase beta2 subunit
alone, although the structure of the tryptophan synthase alpha2beta2 complex
from Salmonella typhimurium has already been reported. The structure of Pfbeta2
was essentially similar to that of the beta2 subunit (Stbeta2) in the
alpha2beta2 complex from S. typhimurium. The sequence alignment with secondary
structures of Pfbeta and Stbeta in monomeric form showed that six residues in
the N-terminal region and three residues in the C-terminal region were deleted
in Pfbeta, and one residue at Pro366 of Stbeta and at Ile63 of Pfbeta was
inserted. The denaturation temperature of Pfbeta2 was higher by 35 degrees C
than the reported values from mesophiles at approximately pH 8. On the basis of
structural information on both proteins, the analyses of the contributions of
each stabilization factor indicate that: (a) the higher stability of Pfbeta2 is
not caused by either a hydrophobic interaction or an increase in ion pairs; (b)
the number of hydrogen bonds involved in the main chains of Pfbeta is greater by
about 10% than that of Stbeta, indicating that the secondary structures of
Pfbeta are more stabilized than those of Stbeta and (c) the sequence of Pfbeta
seems to be better fitted to an ideally stable structure than that of Stbeta, as
assessed from X-ray structure data.
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Figure 3.
Fig. 3. Crystal structure of  [2] subunit
alone of tryptophan synthase from P. furiosus. (A) The overall
structure of the tryptophan synthase [2] dimer
from P. furiosus. The N-terminal (1–200) and the C-terminal
(201–388) residues are coloured red and blue, respectively.
Arrows point to the first two strands and one helical structure
(residue 58–64) that intrude into the C domain. The PLP
molecule is represented as a CPK model, coloured gold. Drawings
were prepared using MOLSCRIPT[71]. (B) Two similar N and C
domains of Pf were
superimposed using 69 C  pairs fitted
well among the 73 residues of St , which are
reported to deviate by less than 4.0 Å between both
domains [3]. The N and C domains are depicted in gold and green,
respectively. Fitting used program LSQKAB[72].
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Figure 5.
Fig. 5. Schematic stereo view of the superimposed monomer
structures of the tryptophan synthase [2] from P.
furiosus and S. typhimurium. Blue and red lines represent the
coordinates of Pf and St (1BKS),
respectively. Drawings were prepared using MOLSCRIPT[71].
Residual numbers are shown with an increase of 10 for the Pf
. An arrow
indicates the most different part between the proteins around
position 60 of Pf .
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The above figures are
reprinted
by permission from the Federation of European Biochemical Societies:
Eur J Biochem
(2004,
271,
2624-2635)
copyright 2004.
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