1. CHIN, C.C., ANDERSON, P.M. AND WOLD, F.
The amino acid sequence of Escherichia coli cyanase.
J.BIOL.CHEM. 258 276-282 (1983).
2. SUNG, Y.C. AND FUCHS, J.A.
Characterization of the cyn operon in Escherichia coli K12.
J.BIOL.CHEM. 263(29) 14769-14775 (1988).
3. LITTLE, R.M. AND ANDERSON, P.M.
Structural properties of cyanase. Denaturation, renaturation, and role of
sulphydrils and oligomeric structure in catalytic activity.
J.BIOL.CHEM. 262 10120-10126 (1987).
4. WALSH, M.A., OTWINOWSKI, Z., PERRAKIS, A., ANDERSON, P.M. AND
Structure of cyanase reveals that a novel dimeric and decameric arrangement
of subunits is required for formation of the enzyme active site.
STRUCTURE 8 505-514 (2000).
Cyanase, an enzyme found in bacteria and plants, catalyses the reaction
of cyanate with bicarbonate to produce ammonia and carbon dioxide, allowing
the host organisms to overcome the toxicity of environmental cyanate .
The enzyme is also known as cyanase lyase and cyanase hydrolase.
The cyanate lyase monomer is composed of two domains: an N-terminal domain
that shows structural similarity to the DNA-binding alpha-helix bundle
motif, and a C-terminal domain that has an 'open fold' that shows no
structural similarity to other proteins [2,4].
The enzyme is active as a homodecamer of 17kDa subunits, and displays
half-site binding of substrates or substrate analogues. The dimer structure
reveals the C-terminal domains to be intertwined; the decamer is formed
from a pentamer of these dimers. The active site of the enzyme is located
between dimers and comprises residues from four adjacent subunits
of the homodecamer .
CYANASE is a 5-element fingerprint that provides a signature for the
cyanases. The fingerprint was derived from an initial alignment of 4
sequences: the motifs were drawn from conserved regions spanning the full
alignment length - motif 1 spans the C-terminus of alpha-helix 1 and helix
2; motif 2 spans helix 3 and the N-terminus of helix 4; motif 3 encodes the
N-terminus of helix 6, and includes the active site arginine and glutamate
residues; motif 4 spans the C-terminus of helix 6 and the N-terminal portion
of beta-strand 1, including the active site serine; and motif 5 encodes
strand 2. Two iterations on SPTR40_18f were required to reach convergence,
at which point a true set comprising 7 sequences was identified.