 |
PDBsum entry 1chk
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Hydrolase (o-glycosyl)
|
PDB id
|
|
|
|
1chk
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
 |
Contents |
 |
|
|
|
|
|
|
|
|
|
|
* Residue conservation analysis
|
|
|
|
|
References listed in PDB file
|
|
|
Key reference
|
|
|
Title
|
|
X-Ray structure of an anti-Fungal chitosanase from streptomyces n174.
|
|
|
Authors
|
|
E.M.Marcotte,
A.F.Monzingo,
S.R.Ernst,
R.Brzezinski,
J.D.Robertus.
|
|
|
Ref.
|
|
Nat Struct Biol, 1996,
3,
155-162.
|
|
|
PubMed id
|
|
|
|
|
Note In the PDB file this reference is
annotated as "TO BE PUBLISHED".
The citation details given above were identified by an automated
search of PubMed on title and author
names, giving a
percentage match of
93%.
|
|
|
|
Abstract
|
|
|
We report the 2.4 A X-ray crystal structure of a protein with chitosan
endo-hydrolase activity isolated from Streptomyces N174. The structure was
solved using phases acquired by SIRAS from a two-site methyl mercury derivative
combined with solvent flattening and non-crystallographic two-fold symmetry
averaging, and refined to an R-factor of 18.5%. The mostly alpha-helical fold
reveals a structural core shared with several classes of lysozyme and barley
endochitinase, in spite of a lack of shared sequence. Based on this structural
similarity we postulate a putative active site, mechanism of action and mode of
substrate recognition. It appears that Glu 22 acts as an acid and Asp 40 serves
as a general base to activate a water molecule for an SN2 attack on the
glycosidic bond. A series of amino-acid side chains and backbone carbonyl groups
may bind the polycationic chitosan substrate in a deep electronegative binding
cleft.
|
|
|
Secondary reference #1
|
|
|
Title
|
|
Crystallization of a chitosanase from streptomyces n174.
|
|
|
Authors
|
|
E.Marcotte,
P.J.Hart,
I.Boucher,
R.Brzezinski,
J.D.Robertus.
|
|
|
Ref.
|
|
J Mol Biol, 1993,
232,
995-996.
|
|
|
PubMed id
|
|
|
|
|
|
|
|
|
|
|
|
|
