Structure of Acetylglutamate Kinase, a Key Enzyme for Arginine Biosynthesis and a Prototype for the Amino Acid Kinase Enzyme Family, during Catalysis

N-Acetyl-L-glutamate kinase (NAGK), a member of the amino acid kinase family, catalyzes the second and frequently controlling step of arginine synthesis. The Escherichia coli NAGK crystal structure to 1.5 Å resolution reveals a 258-residue subunit homodimer nucleated by a central 16-stranded molecul...

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Bibliographic Details
Published in:Structure (London) 2002-03, Vol.10 (3), p.329-342
Main Authors: Ramón-Maiques, Santiago, Marina, Alberto, Gil-Ortiz, Fernando, Fita, Ignacio, Rubio, Vicente
Format: Article
Language:English
Subjects:
acetylglutamate kinase
amino acid kinase
Amino Acid Sequence
Arginine - biosynthesis
Binding Sites
carbamate kinase
Catalysis
Crystallography, X-Ray
Dimerization
Escherichia coli - enzymology
Molecular Sequence Data
Molecular Structure
Multigene Family
phosphoryl group transfer
Phosphotransferases (Carboxyl Group Acceptor) - chemistry
Phosphotransferases (Carboxyl Group Acceptor) - genetics
Phosphotransferases (Carboxyl Group Acceptor) - metabolism
protein crystallography
Protein Structure, Secondary
Protein Structure, Tertiary
Sequence Alignment
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Summary:N-Acetyl-L-glutamate kinase (NAGK), a member of the amino acid kinase family, catalyzes the second and frequently controlling step of arginine synthesis. The Escherichia coli NAGK crystal structure to 1.5 Å resolution reveals a 258-residue subunit homodimer nucleated by a central 16-stranded molecular open β sheet sandwiched between α helices. In each subunit, AMPPNP, as an αβγ-phosphate-Mg 2+ complex, binds along the sheet C edge, and N-acetyl-L-glutamate binds near the dyadic axis with its γ-COO − aligned at short distance from the γ-phosphoryl, indicating associative phosphoryl transfer assisted by: (1) Mg 2+ complexation; (2) the positive charges on Lys8, Lys217, and on two helix dipoles; and (3) by hydrogen bonding with the γ-phosphate. The structural resemblance with carbamate kinase and the alignment of the sequences suggest that NAGK is a structural and functional prototype for the amino acid kinase family, which differs from other acylphosphate-making devices represented by phosphoglycerate kinase, acetate kinase, and biotin carboxylase.
ISSN:0969-2126
1878-4186
DOI:10.1016/S0969-2126(02)00721-9