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PDBsum entry 1xrb
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References listed in PDB file
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Key reference
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Title
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Crystal structure of s-Adenosylmethionine synthetase.
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Authors
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F.Takusagawa,
S.Kamitori,
S.Misaki,
G.D.Markham.
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Ref.
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J Biol Chem, 1996,
271,
136-147.
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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
perfect match.
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Abstract
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The structure of S-adenosylmethionine synthetase (MAT, ATP:L-methionine
S-adenosyltransferase, EC 2.5.1.6.) from Escherichia coli has been determined at
3.0 A resolution by multiple isomorphous replacement using a uranium derivative
and the selenomethionine form of the enzyme (SeMAT). The SeMAT data (9
selenomethionine residues out of 383 amino acid residues) have been found to
have a sufficient phasing power to determine the structure of the 42,000
molecular weight protein by combining them with the other heavy atom derivative
data (multiple isomorphous replacement). The enzyme consists of four identical
subunits; two subunits form a spherical tight dimer, and pairs of these dimers
form a peanut-shaped tetrameric enzyme. Each pair dimer has two active sites
which are located between the subunits. Each subunit consists of three domains
that are related to each other by pseudo-3-fold symmetry. The essential divalent
(Mg2+/Co2+) and monovalent (K+) metal ions and one of the product, Pi ions, were
found in the active site from three separate structures.
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