1ctn: Difference between revisions
New page: left|200px<br /><applet load="1ctn" size="450" color="white" frame="true" align="right" spinBox="true" caption="1ctn, resolution 2.3Å" /> '''CRYSTAL STRUCTURE OF ... |
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[[Image:1ctn.gif|left|200px]]<br /><applet load="1ctn" size=" | [[Image:1ctn.gif|left|200px]]<br /><applet load="1ctn" size="350" color="white" frame="true" align="right" spinBox="true" | ||
caption="1ctn, resolution 2.3Å" /> | caption="1ctn, resolution 2.3Å" /> | ||
'''CRYSTAL STRUCTURE OF A BACTERIAL CHITINASE AT 2.3 ANGSTROMS RESOLUTION'''<br /> | '''CRYSTAL STRUCTURE OF A BACTERIAL CHITINASE AT 2.3 ANGSTROMS RESOLUTION'''<br /> | ||
==Overview== | ==Overview== | ||
BACKGROUND: Chitinases cleave the beta-1-4-glycosidic bond between the | BACKGROUND: Chitinases cleave the beta-1-4-glycosidic bond between the N-acetyl-D-glucosamine units of which chitin is comprised. Chitinases are present in plants, bacteria and fungi, but whereas structures are available for two prototypic plant enzymes, no structure is available for a bacterial or fungal chitinase. RESULTS: To redress this imbalance, the structure of native chitinase A from Serratia marcescens has been solved by multiple isomorphous replacement and refined at 2.3 A resolution, resulting in a crystallographic R-factor of 16.2%. The enzyme comprises three domains: an all beta-strand amino-terminal domain, a catalytic alpha/beta-barrel domain, and a small alpha+beta-fold domain. There are several residues with unusual geometries in the structure. Structure determination of chitinase A in complex with N,N',N",N"'-tetra-acetylo-chitotetraose, together with biochemical and sequence analysis data, enabled the positions of the active-site and catalytic residues to be proposed. CONCLUSIONS: The reaction mechanism seems to be similar to that of lysozyme and most other glycosylhydrolases, i.e. general acid-base catalysis. The role of the amino-terminal domain could not be identified, but it has similarities to the fibronectin III domain. This domain may possibly facilitate the interaction of chitinase A with chitin. | ||
==About this Structure== | ==About this Structure== | ||
1CTN is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Serratia_marcescens Serratia marcescens]. Active as [http://en.wikipedia.org/wiki/Chitinase Chitinase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.1.14 3.2.1.14] Full crystallographic information is available from [http:// | 1CTN is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Serratia_marcescens Serratia marcescens]. Active as [http://en.wikipedia.org/wiki/Chitinase Chitinase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.1.14 3.2.1.14] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1CTN OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: Perrakis, A.]] | [[Category: Perrakis, A.]] | ||
[[Category: Tews, I.]] | [[Category: Tews, I.]] | ||
[[Category: Vorgias, C | [[Category: Vorgias, C E.]] | ||
[[Category: Wilson, K | [[Category: Wilson, K S.]] | ||
[[Category: lyase (oxo-acid)]] | [[Category: lyase (oxo-acid)]] | ||
''Page seeded by [http:// | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 12:09:34 2008'' | ||
Revision as of 13:09, 21 February 2008
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CRYSTAL STRUCTURE OF A BACTERIAL CHITINASE AT 2.3 ANGSTROMS RESOLUTION
OverviewOverview
BACKGROUND: Chitinases cleave the beta-1-4-glycosidic bond between the N-acetyl-D-glucosamine units of which chitin is comprised. Chitinases are present in plants, bacteria and fungi, but whereas structures are available for two prototypic plant enzymes, no structure is available for a bacterial or fungal chitinase. RESULTS: To redress this imbalance, the structure of native chitinase A from Serratia marcescens has been solved by multiple isomorphous replacement and refined at 2.3 A resolution, resulting in a crystallographic R-factor of 16.2%. The enzyme comprises three domains: an all beta-strand amino-terminal domain, a catalytic alpha/beta-barrel domain, and a small alpha+beta-fold domain. There are several residues with unusual geometries in the structure. Structure determination of chitinase A in complex with N,N',N",N"'-tetra-acetylo-chitotetraose, together with biochemical and sequence analysis data, enabled the positions of the active-site and catalytic residues to be proposed. CONCLUSIONS: The reaction mechanism seems to be similar to that of lysozyme and most other glycosylhydrolases, i.e. general acid-base catalysis. The role of the amino-terminal domain could not be identified, but it has similarities to the fibronectin III domain. This domain may possibly facilitate the interaction of chitinase A with chitin.
About this StructureAbout this Structure
1CTN is a Single protein structure of sequence from Serratia marcescens. Active as Chitinase, with EC number 3.2.1.14 Full crystallographic information is available from OCA.
ReferenceReference
Crystal structure of a bacterial chitinase at 2.3 A resolution., Perrakis A, Tews I, Dauter Z, Oppenheim AB, Chet I, Wilson KS, Vorgias CE, Structure. 1994 Dec 15;2(12):1169-80. PMID:7704527
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