Abstract
The crystal structure of Acetobacter aceti PurE was determined to a resolution of 1.55 A and is compared with the known structures of the class I PurEs from a mesophile, Escherichia coli, and a thermophile, Thermotoga maritima. Analyses of the general factors that increase protein stability are examined as potential explanations for the acid stability of A. aceti PurE. Increased inter-subunit hydrogen bonding and an increased number of arginine-containing salt bridges appear to account for the bulk of the increased acid stability. A chain of histidines linking two active sites is discussed in the context of the proton transfers catalyzed by the enzyme.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Acetobacter / enzymology*
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Amino Acid Sequence
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Arginine / chemistry
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Binding Sites
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Crystallography, X-Ray / methods
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Escherichia coli / enzymology
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Histidine / chemistry
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Hydrogen Bonding
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Intramolecular Transferases / biosynthesis
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Intramolecular Transferases / chemistry*
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Models, Molecular
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Molecular Sequence Data
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Protein Conformation
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Protein Folding
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Protein Structure, Quaternary
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Protein Structure, Secondary
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Protons
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Sequence Homology, Amino Acid
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Thermotoga maritima / enzymology
Substances
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Protons
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Histidine
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Arginine
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Intramolecular Transferases
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N(5)-carboxyaminoimidazole ribonucletide mutase