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PDBsum entry 4ga5
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References listed in PDB file
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Key reference
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Title
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Structure analysis of archaeal AMP phosphorylase reveals two unique modes of dimerization.
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Authors
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Y.Nishitani,
R.Aono,
A.Nakamura,
T.Sato,
H.Atomi,
T.Imanaka,
K.Miki.
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Ref.
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J Mol Biol, 2013,
425,
2709-2721.
[DOI no: ]
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PubMed id
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Abstract
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AMP phosphorylase (AMPpase) catalyzes the initial reaction in a novel AMP
metabolic pathway recently found in archaea, converting AMP and phosphate into
adenine and ribose 1,5-bisphosphate. Gel-filtration chromatography revealed that
AMPpase from Thermococcus kodakarensis (Tk-AMPpase) forms an exceptionally large
macromolecular structure (>40-mers) in solution. To investigate its unique
multimerization feature, we determined the first crystal structures of
Tk-AMPpase, in the apo-form and in complex with substrates. Structures of two
truncated forms of Tk-AMPpase (Tk-AMPpaseΔN84 and Tk-AMPpaseΔC10) clarified
that this multimerization is achieved by two dimer interfaces within a single
molecule: one by the central domain and the other by the C-terminal domain,
which consists of an unexpected domain-swapping interaction. The N-terminal
domain, characteristic of archaeal enzymes, is essential for enzymatic activity,
participating in multimerization as well as domain closure of the active site
upon substrate binding. Moreover, biochemical analysis demonstrated that the
macromolecular assembly of Tk-AMPpase contributes to its high thermostability,
essential for an enzyme from a hyperthermophile. Our findings unveil a unique
archaeal nucleotide phosphorylase that is distinct in both function and
structure from previously known members of the nucleoside phosphorylase II
family.
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