1MGV

Crystal Structure of the R391A Mutant of 7,8-Diaminopelargonic Acid Synthase

Summary for 1MGV

• Entry DOI: 10.2210/pdb1mgv/pdb
• Related: 1dty 1qj3 1qj5
• Descriptor: 7,8-diamino-pelargonic acid aminotransferase, SODIUM ION, PYRIDOXAL-5'-PHOSPHATE, ... (5 entities in total)
• Functional Keywords: aminotransferase, fold type i, subclass ii, homodimer, transferase
• Biological source: Escherichia coli
• Cellular location: Cytoplasm : P12995
• Total number of polymer chains: 2
• Total formula weight: 95229.19

Authors

Eliot, A.C.,Sandmark, J.,Schneider, G.,Kirsch, J.F. (deposition date: 2002-08-16, release date: 2002-11-27, Last modification date: 2024-04-03)

Primary citation

Eliot, A.C.,Sandmark, J.,Schneider, G.,Kirsch, J.F.
The Dual-Specific Active Site of 7,8-Diaminopelargonic Acid Synthase and the Effect of the R391A Mutation
Biochemistry, 41:12582-12589, 2002

PubMed Abstract: 7,8-diaminopelargonic acid (DAPA) synthase (EC 2.6.1.62) is a pyridoxal phosphate (PLP)-dependent transaminase that catalyzes the transfer of the alpha-amino group from S-adenosyl-L-methionine (SAM) to 7-keto-8-aminopelargonic acid (KAPA) to form DAPA in the antepenultimate step in the biosynthesis of biotin. The wild-type enzyme has a steady-state kcat value of 0.013 s(-1), and the K(m) values for SAM and KAPA are 150 and <2 microM, respectively. The k(max) and apparent K(m) values for the half-reaction of the PLP form of the enzyme with SAM are 0.016 s(-1) and 300 microM, respectively, while those for the reaction with DAPA are 0.79 s(-1) and 1 microM. The R391A mutant enzyme exhibits near wild-type kinetic parameters in the reaction with SAM, while the apparent K(m) for DAPA is increased 180-fold. The 2.1 A crystal structure of the R391A mutant enzyme shows that the mutation does not significantly alter the structure. These results indicate that the conserved arginine residue is not required for binding the alpha-amino acid SAM, but it is important for recognition of DAPA.

PubMed: 12379100
DOI: 10.1021/bi026339a

Experimental method

X-RAY DIFFRACTION (2.1 Å)