1qgi
From Proteopedia
(New page: 200px<br /><applet load="1qgi" size="450" color="white" frame="true" align="right" spinBox="true" caption="1qgi, resolution 1.6Å" /> '''CHITOSANASE FROM BACI...) |
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| - | [[Image:1qgi.gif|left|200px]]<br /><applet load="1qgi" size=" | + | [[Image:1qgi.gif|left|200px]]<br /><applet load="1qgi" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1qgi, resolution 1.6Å" /> | caption="1qgi, resolution 1.6Å" /> | ||
'''CHITOSANASE FROM BACILLUS CIRCULANS'''<br /> | '''CHITOSANASE FROM BACILLUS CIRCULANS'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Chitosanase from Bacillus circulans MH-K1 is a 29-kDa extracellular | + | Chitosanase from Bacillus circulans MH-K1 is a 29-kDa extracellular protein composed of 259 amino acids. The crystal structure of chitosanase from B. circulans MH-K1 has been determined by multiwavelength anomalous diffraction method and refined to crystallographic R = 19.2% (R(free) = 23.5%) for the diffraction data at 1.6-A resolution collected by synchrotron radiation. The enzyme has two globular upper and lower domains, which generate the active site cleft for the substrate binding. The overall molecular folding is similar to chitosanase from Streptomyces sp. N174, although there is only 20% identity at the amino acid sequence level between both chitosanases. However, there are three regions in which the topology is remarkably different. In addition, the disulfide bridge between Cys(50) and Cys(124) joins the beta1 strand and the alpha7 helix, which is not conserved among other chitosanases. The orientation of two backbone helices, which connect the two domains, is also different and is responsible for the differences in size and shape of the active site cleft in these two chitosanases. This structural difference in the active site cleft is the reason why the enzymes specifically recognize different substrates and catalyze different types of chitosan degradation. |
==About this Structure== | ==About this Structure== | ||
| - | 1QGI is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Bacillus_circulans Bacillus circulans] with NAG and SO4 as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Chitosanase Chitosanase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.1.132 3.2.1.132] Full crystallographic information is available from [http:// | + | 1QGI is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Bacillus_circulans Bacillus circulans] with <scene name='pdbligand=NAG:'>NAG</scene> and <scene name='pdbligand=SO4:'>SO4</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Chitosanase Chitosanase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.1.132 3.2.1.132] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1QGI OCA]. |
==Reference== | ==Reference== | ||
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[[Category: hydrolase]] | [[Category: hydrolase]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 14:39:14 2008'' |
Revision as of 12:39, 21 February 2008
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CHITOSANASE FROM BACILLUS CIRCULANS
Overview
Chitosanase from Bacillus circulans MH-K1 is a 29-kDa extracellular protein composed of 259 amino acids. The crystal structure of chitosanase from B. circulans MH-K1 has been determined by multiwavelength anomalous diffraction method and refined to crystallographic R = 19.2% (R(free) = 23.5%) for the diffraction data at 1.6-A resolution collected by synchrotron radiation. The enzyme has two globular upper and lower domains, which generate the active site cleft for the substrate binding. The overall molecular folding is similar to chitosanase from Streptomyces sp. N174, although there is only 20% identity at the amino acid sequence level between both chitosanases. However, there are three regions in which the topology is remarkably different. In addition, the disulfide bridge between Cys(50) and Cys(124) joins the beta1 strand and the alpha7 helix, which is not conserved among other chitosanases. The orientation of two backbone helices, which connect the two domains, is also different and is responsible for the differences in size and shape of the active site cleft in these two chitosanases. This structural difference in the active site cleft is the reason why the enzymes specifically recognize different substrates and catalyze different types of chitosan degradation.
About this Structure
1QGI is a Single protein structure of sequence from Bacillus circulans with and as ligands. Active as Chitosanase, with EC number 3.2.1.132 Full crystallographic information is available from OCA.
Reference
Crystal structure of chitosanase from Bacillus circulans MH-K1 at 1.6-A resolution and its substrate recognition mechanism., Saito J, Kita A, Higuchi Y, Nagata Y, Ando A, Miki K, J Biol Chem. 1999 Oct 22;274(43):30818-25. PMID:10521473
Page seeded by OCA on Thu Feb 21 14:39:14 2008
Categories: Bacillus circulans | Chitosanase | Single protein | Ando, A. | Higuchi, Y. | Kita, A. | Miki, K. | Nagata, Y. | Saito, J. | NAG | SO4 | Chitosan degradation | Hydrolase
