The cyanide degrading nitrilase from Pseudomonas stutzeri AK61 is a two-fold symmetric, 14-subunit spiral.
The quaternary structure of the cyanide dihydratase from Pseudomonas stutzeri AK61 was determined by negative stain electron microscopy and three-dimensional reconstruction using the single particle technique. The structure is a spiral comprising 14 subunits with 2-fold symmetry. Interactions across the groove cause a decrease in the radius of the spiral at the ends and the resulting steric hindrance prevents the addition of further subunits. Similarity to two members of the nitrilase superfamily, the Nit domain of NitFhit and N-carbamyl-D-amino acid amidohydrolase, enabled the construction of a partial atomic model that could be unambiguously fitted to the stain envelope. The model suggests that interactions involving two significant insertions in the sequence relative to these structures leads to the left-handed spiral assembly.
Sewell
B T
BT
Electron Microscope Unit, University of Cape Town, Private Bag, 7701 Rondebosch, South Africa. sewell@uctvms.uct.ac.za
Berman
M N
MN
Meyers
P R
PR
Jandhyala
D
D
Benedik
M J
MJ
D000595:Amino Acid Sequence; D000619:Aminohydrolases / Q000737:chemistry*; D006860:Hydrogen Bonding; D008854:Microscopy, Electron; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011487:Protein Conformation; D020836:Protein Structure, Quaternary; D017434:Protein Structure, Tertiary; D044223:Pseudomonas stutzeri / Q000201:enzymology*; D017386:Sequence Homology, Amino Acid
D000619:Aminohydrolases; C021867:nitrilase