Acta Crystallographica Section D

Biological Crystallography

Volume 65, Part 11 (November 2009)

research papers

Acta Cryst. (2009). D65, 1181-1186 [ doi:10.1107/S090744490903306X ]

The structure of Mg-ATPase nucleotide-binding domain at 1.6 Å resolution reveals a unique ATP-binding motif

K. O. Håkansson

Abstract: The structure of the nucleotide-binding domain of the Mg-ATPase MgtA from Escherichia coli has been solved and refined to 1.6 Å resolution. The structure is made up of a six-stranded [beta] -sheet and a bundle of three [alpha] -helices, with the nucleotide-binding site sandwiched in between. The MgtA nucleotide-binding domain is shorter and more compact compared with that of the related Ca-ATPase and lacks one of the [beta] -strands at the edge of the [beta] -sheet. The ATP-binding pocket is surrounded by three sequence and structural motifs known from other P-type ATPases and a fourth unique motif that is found only in Mg-ATPases. This motif consists of a short polypeptide stretch running very close to the ATP-binding site, while in Ca-ATPase the binding site is more open, with the corresponding polypeptide segment folded away from the active site.

PDB reference: 3gwi

Keywords: P-type ATPases; ATP binding; MgtA; MgtB; membrane proteins.