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PDBsum entry 1ttp
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Carbon-oxygen lyase
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PDB id
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1ttp
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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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Exchange of k+ or cs+ for na+ induces local and long-Range changes in the three-Dimensional structure of the tryptophan synthase alpha2beta2 complex.
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Authors
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S.Rhee,
K.D.Parris,
S.A.Ahmed,
E.W.Miles,
D.R.Davies.
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Ref.
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Biochemistry, 1996,
35,
4211-4221.
[DOI no: ]
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PubMed id
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Note In the PDB file this reference is
annotated as "TO BE PUBLISHED".
The citation details given above were identified by an automated
search of PubMed on title and author
names, giving a
percentage match of
96%.
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Abstract
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Monovalent cations activate the pyridoxal phosphate-dependent reactions of
tryptophan synthase and affect intersubunit communication in the alpha2beta2
complex. We report refined crystal structures of the tryptophan synthase
alpha2beta2 complex from Salmonella typhimurium in the presence of K+ at 2.0
angstrom and of Cs+ at 2.3 angstrom. Comparison of these structures with the
recently refined structure in the presence of Na+ shows that each monovalent
cation binds at approximately the same position about 8 angstrom from the
phosphate of pyridoxal phosphate. Na+ and K+ are coordinated to the carbonyl
oxygens of beta Phe-306, beta Ser-308, and beta Gly-232 and to two or one water
molecule, respectively. Cs+ is coordinated to the carbonyl oxygens of beta
Phe-306, beta Ser-308, beta Gly-232, beta Val-231, beta Gly-268 and beta
Leu-304. A second binding site for Cs+ is located in the beta/beta interface on
the 2-fold axis with four carbonyl oxygens in the coordination sphere. In
addition to local changes in structure close to the cation binding site, a
number of long-range changes are observed. The K+ and Cs+ structures differ from
the Na+ structure with respect to the positions of beta Asp-305, beta Lys-167,
and alpha Asp-56. One unexpected result of this investigation is the movement of
the side chains of beta Phe-280 and beta Tyr-279 from a position partially
blocking the tunnel in the Na+ structure to a position lining the surface of the
tunnel in the K+ and Cs+ structures. The results provide a structural basis for
understanding the effects of cations on activity and intersubunit communication.
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Secondary reference #1
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Title
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The tryptophan synthase multienzyme complex: exploring structure-Function relationships with x-Ray crystallography and mutagenesis.
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Authors
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C.C.Hyde,
E.W.Miles.
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Ref.
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Biotechnology (n Y), 1990,
8,
27-32.
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PubMed id
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Secondary reference #2
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Title
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Three-Dimensional structure of the tryptophan synthase alpha 2 beta 2 multienzyme complex from salmonella typhimurium.
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Authors
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C.C.Hyde,
S.A.Ahmed,
E.A.Padlan,
E.W.Miles,
D.R.Davies.
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Ref.
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J Biol Chem, 1988,
263,
17857-17871.
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PubMed id
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Secondary reference #3
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Title
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Crystallization and preliminary X-Ray crystallographic data of the tryptophan synthase alpha 2 beta 2 complex from salmonella typhimurium.
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Authors
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S.A.Ahmed,
E.W.Miles,
D.R.Davies.
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Ref.
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J Biol Chem, 1985,
260,
3716-3718.
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PubMed id
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