 |
|
|
|
|
 |
Contents |
 |
|
|
|
|
|
|
|
|
|
|
|
* Residue conservation analysis
|
|
|
|
 |
|
 |
|
 |
|
|
Gene Ontology (GO) functional annotation
|
|
|
|
 |
 |
 |
|
 |
 |
 |
 |
|
 |
|
Biological process
|
carbohydrate metabolic process
|
3 terms
|
 |
|
Biochemical function
|
chitinase activity
|
1 term
|
 |
|
|
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
|
|
|
| |
|
DOI no:
|
Febs J
274:3695-3703
(2007)
|
|
PubMed id:
|
|
|
|
|
| |
|
Crystal structures of a family 19 chitinase from Brassica juncea show flexibility of binding cleft loops.
|
|
W.Ubhayasekera,
C.M.Tang,
S.W.Ho,
G.Berglund,
T.Bergfors,
M.L.Chye,
S.L.Mowbray.
|
|
|
|
| |
ABSTRACT
|
|
|
| |
|
Brassica juncea chitinase is an endo-acting, pathogenesis-related protein that
is classified into glycoside hydrolase family 19, with highest homology (50-60%)
in its catalytic domain to class I plant chitinases. Here we report X-ray
structures of the chitinase catalytic domain from wild-type (apo, as well as
with chloride ions bound) and a Glu234Ala mutant enzyme, solved by molecular
replacement and refined at 1.53, 1.8 and 1.7 A resolution, respectively.
Confirming our earlier mutagenesis studies, the active-site residues are
identified as Glu212 and Glu234. Glu212 is believed to be the catalytic acid in
the reaction, whereas Glu234 is thought to have a dual role, both activating a
water molecule in its attack on the anomeric carbon, and stabilizing the charged
intermediate. The molecules in the various structures differ significantly in
the conformation of a number of loops that border the active-site cleft. The
differences suggest an opening and closing of the enzyme during the catalytic
cycle. Chitin is expected to dock first near Glu212, which will protonate it.
Conformational changes then bring Glu234 closer, allowing it to assist in the
following steps. These observations provide important insights into catalysis in
family 19 chitinases.
|
|
|
|
|
|
|
 |
 |
|
 |
 |
 |
 |
 |
 |
 |
 |
 |
|
Literature references that cite this PDB file's key reference
|
|
 |
| |
PubMed id
|
 |
Reference
|
 |
|
|
|
 |
T.Taira,
Y.Mahoe,
N.Kawamoto,
S.Onaga,
H.Iwasaki,
T.Ohnuma,
and
T.Fukamizo
(2011).
Cloning and characterization of a small family 19 chitinase from moss (Bryum coronatum).
|
| |
Glycobiology, 21,
644-654.
|
 |
|
|
|
|
 |
Y.Kezuka,
M.Kojima,
R.Mizuno,
K.Suzuki,
T.Watanabe,
and
T.Nonaka
(2010).
Structure of full-length class I chitinase from rice revealed by X-ray crystallography and small-angle X-ray scattering.
|
| |
Proteins, 78,
2295-2305.
|
 |
|
PDB code:
|
 |
|
|
|
|
|
 |
W.Ubhayasekera,
R.Rawat,
S.W.Ho,
M.Wiweger,
S.Von Arnold,
M.L.Chye,
and
S.L.Mowbray
(2009).
The first crystal structures of a family 19 class IV chitinase: the enzyme from Norway spruce.
|
| |
Plant Mol Biol, 71,
277-289.
|
 |
|
PDB codes:
|
 |
|
|
|
|
|
 |
J.Huet,
M.Azarkan,
Y.Looze,
V.Villeret,
and
R.Wintjens
(2008).
Crystallization and preliminary X-ray analysis of a family 19 glycosyl hydrolase from Carica papaya latex.
|
| |
Acta Crystallogr Sect F Struct Biol Cryst Commun, 64,
371-374.
|
 |
|
|
|
|
 |
Y.Guan,
S.Ramalingam,
D.Nagegowda,
P.W.Taylor,
and
M.L.Chye
(2008).
Brassica juncea chitinase BjCHI1 inhibits growth of fungal phytopathogens and agglutinates Gram-negative bacteria.
|
| |
J Exp Bot, 59,
3475-3484.
|
 |
|
 |
 |
|
The most recent references are shown first.
Citation data come partly from CiteXplore and partly
from an automated harvesting procedure. Note that this is likely to be
only a partial list as not all journals are covered by
either method. However, we are continually building up the citation data
so more and more references will be included with time.
Where a reference describes a PDB structure, the PDB
code is
shown on the right.
|
|