1. DAUTER, Z., DAUTER, M., HEMKER, J., WITZEL, H. AND WILSON, K.S.
Crystallization and preliminary-analysis of glucose-isomerase from
FEBS LETT. 247 1-8 (1989).
2. HENRICK, K., COLLYER, C.A. AND BLOW, D.M.
Structures of D-xylose isomerase from Arthrobacter strain-b3728 containing
the inhibitors xylitol and D-sorbitol at 2.5A and 2.3A resolution, res..
J.MOL.BIOL. 208 129-157 (1989).
3. VANGRYSPERRE, W., AMPE, C., KERSTERS-HILDERSON, H. AND TEMPST, P.
Single active-site histidine in D-xylose isomerase from Streptomyces
violaceoruber - identification by chemical derivatization and
BIOCHEM.J. 263 195-199 (1989).
Xylose isomerase is an enzyme found in microorganisms that catalyses the
interconversion of D-xylose to D-xylulose ; it can also isomerise
D-ribose to D-ribulose and D-glucose to D-fructose. The enzyme is a homo-
tetramer, which is stabilised by cobalt, and requires magnesium for its
catalytic activity. Each subunit contains 2 domains: the core domain is a
parallel alpha-beta barrel; the C-terminal domain is a loop structure
consisting of 5 helices and is involved in intermolecular contacts between
adjacent subunits . The active site lies in a deep pocket near the
C-terminal ends of the strands of the barrel domain and includes residues
from a second subunit. The tetramer is effectively a dimer of "active"
dimers, the active sites being composed of residues from both subunits .
XYLOSISMRASE is a 9-element fingerprint that provides a signature for
xylose isomerases. The fingerprint was derived from an initial alignment
of 18 sequences: the motifs were drawn from conserved regions spanning the
full alignment length - motif 1 includes the region encoded by PROSITE
pattern XYLOSE_ISOMERASE_1 (PS00172), which includes a conserved His
residue known to be involved in the catalytic mechanism of the enzyme ;
and motif 6 includes the short conserved region encoded by PROSITE pattern
XYLOSE_ISOMERASE_2 (PS00173), which contains both a glutamic acid residue
that binds magnesium and a lysine involved with the enzyme catalytic
activity . Two iterations on OWL29.2 were required to reach convergence,
at which point a true set comprising 35 sequences was identified. A single
partial match was also found, ECDXI11, a xylose isomerase fragment from
An update on SPTR37_9f identified a true set of 32 sequences.