1ks8
From Proteopedia
(New page: 200px<br /><applet load="1ks8" size="450" color="white" frame="true" align="right" spinBox="true" caption="1ks8, resolution 1.40Å" /> '''The structure of End...) |
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| - | [[Image:1ks8.gif|left|200px]]<br /><applet load="1ks8" size=" | + | [[Image:1ks8.gif|left|200px]]<br /><applet load="1ks8" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1ks8, resolution 1.40Å" /> | caption="1ks8, resolution 1.40Å" /> | ||
'''The structure of Endoglucanase from termite, Nasutitermes takasagoensis, at pH 2.5.'''<br /> | '''The structure of Endoglucanase from termite, Nasutitermes takasagoensis, at pH 2.5.'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Contrary to conventional wisdom, it has been shown recently that termites | + | Contrary to conventional wisdom, it has been shown recently that termites do not necessarily depend on symbiotic bacteria to process cellulose. They secrete their own cellulases, mainly endo-beta-1,4-glucanase and beta-1,4-glucosidase. Here, the first structure of an endogenous endoglucanase from the higher termite Nasutitermes takasagoensis (NtEgl) is reported at 1.40 A resolution. NtEgl has the general folding of an (alpha/alpha)(6) barrel, which is a common folding pattern for glycosyl hydrolase family 9. Three-dimensional structural analysis shows that the conserved Glu412 is the catalytic acid/base residue and the conserved Asp54 or Asp57 is the base. The enzyme has a Ca(2+)-binding site near its substrate-binding cleft. Comparison between the structure of the Ca(2+)-free enzyme produced by reducing the pH of the soaked crystal from 5.6 (the pH of optimum enzyme activity) to 2.5 with that of the Ca(2+)-bound enzyme did not show significant differences in the locations of the C(alpha) atoms. The main differences are in the conformation of the residue side chains ligating the Ca(2+) ion. The overall structure of NtEgl at pH 6.5 is similar to that at pH 5.6. The major change observed was in the conformation of the side chain of the catalytic acid/base Glu412, which rotates from a hydrophobic cavity to a relatively hydrophilic environment. This side-chain displacement may decrease the enzyme activity at higher pH. |
==About this Structure== | ==About this Structure== | ||
| - | 1KS8 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Nasutitermes_takasagoensis Nasutitermes takasagoensis] with SO4 as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Cellulase Cellulase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.1.4 3.2.1.4] Full crystallographic information is available from [http:// | + | 1KS8 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Nasutitermes_takasagoensis Nasutitermes takasagoensis] with <scene name='pdbligand=SO4:'>SO4</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Cellulase Cellulase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.1.4 3.2.1.4] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1KS8 OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Nasutitermes takasagoensis]] | [[Category: Nasutitermes takasagoensis]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: Guarino, L | + | [[Category: Guarino, L A.]] |
[[Category: Khademi, S.]] | [[Category: Khademi, S.]] | ||
| - | [[Category: Meyer, E | + | [[Category: Meyer, E F.]] |
[[Category: Tokuda, G.]] | [[Category: Tokuda, G.]] | ||
[[Category: Watanabe, H.]] | [[Category: Watanabe, H.]] | ||
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[[Category: termite]] | [[Category: termite]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 13:37:22 2008'' |
Revision as of 11:37, 21 February 2008
|
The structure of Endoglucanase from termite, Nasutitermes takasagoensis, at pH 2.5.
Overview
Contrary to conventional wisdom, it has been shown recently that termites do not necessarily depend on symbiotic bacteria to process cellulose. They secrete their own cellulases, mainly endo-beta-1,4-glucanase and beta-1,4-glucosidase. Here, the first structure of an endogenous endoglucanase from the higher termite Nasutitermes takasagoensis (NtEgl) is reported at 1.40 A resolution. NtEgl has the general folding of an (alpha/alpha)(6) barrel, which is a common folding pattern for glycosyl hydrolase family 9. Three-dimensional structural analysis shows that the conserved Glu412 is the catalytic acid/base residue and the conserved Asp54 or Asp57 is the base. The enzyme has a Ca(2+)-binding site near its substrate-binding cleft. Comparison between the structure of the Ca(2+)-free enzyme produced by reducing the pH of the soaked crystal from 5.6 (the pH of optimum enzyme activity) to 2.5 with that of the Ca(2+)-bound enzyme did not show significant differences in the locations of the C(alpha) atoms. The main differences are in the conformation of the residue side chains ligating the Ca(2+) ion. The overall structure of NtEgl at pH 6.5 is similar to that at pH 5.6. The major change observed was in the conformation of the side chain of the catalytic acid/base Glu412, which rotates from a hydrophobic cavity to a relatively hydrophilic environment. This side-chain displacement may decrease the enzyme activity at higher pH.
About this Structure
1KS8 is a Single protein structure of sequence from Nasutitermes takasagoensis with as ligand. Active as Cellulase, with EC number 3.2.1.4 Full crystallographic information is available from OCA.
Reference
Structure of an endoglucanase from termite, Nasutitermes takasagoensis., Khademi S, Guarino LA, Watanabe H, Tokuda G, Meyer EF, Acta Crystallogr D Biol Crystallogr. 2002 Apr;58(Pt 4):653-9. Epub 2002, Mar 22. PMID:11914490
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