1lxk
From Proteopedia
(New page: 200px<br /><applet load="1lxk" size="450" color="white" frame="true" align="right" spinBox="true" caption="1lxk, resolution 1.53Å" /> '''Streptococcus pneumo...) |
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| - | [[Image:1lxk.gif|left|200px]]<br /><applet load="1lxk" size=" | + | [[Image:1lxk.gif|left|200px]]<br /><applet load="1lxk" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1lxk, resolution 1.53Å" /> | caption="1lxk, resolution 1.53Å" /> | ||
'''Streptococcus pneumoniae Hyaluronate Lyase in Complex with Tetrasaccharide Hyaluronan Substrate'''<br /> | '''Streptococcus pneumoniae Hyaluronate Lyase in Complex with Tetrasaccharide Hyaluronan Substrate'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Hyaluronate lyase enzymes degrade hyaluronan, the main polysaccharide | + | Hyaluronate lyase enzymes degrade hyaluronan, the main polysaccharide component of the host connective tissues, predominantly into unsaturated disaccharide units, thereby destroying the normal connective tissue structure and exposing the tissue cells to various endo- and exogenous factors, including bacterial toxins. The crystal structures of Streptococcus pneumoniae hyaluronate lyase with tetra- and hexasaccharide hyaluronan substrates bound in the active site were determined at 1.52- and 2.0-A resolution, respectively. Hexasaccharide is the longest substrate segment that binds entirely within the active site of these enzymes. The enzyme residues responsible for substrate binding, positioning, catalysis, and product release were thereby identified and their specific roles characterized. The involvement of three residues in catalysis, Asn(349), His(399), and Tyr(408), is confirmed, and the details of proton acceptance and donation within the catalytic machinery are described. The mechanism of processivity of the enzyme is analyzed. The flexibility (allosteric) behavior of the enzyme may be understood in terms of the results of flexibility analysis of this protein, which identified two modes of motion that are also proposed to be involved in the hyaluronan degradation process. The first motion describes an opening and closing of the catalytic cleft located between the alpha- and beta-domains. The second motion demonstrates the mobility of a binding cleft, which may facilitate the binding of the negatively charged hyaluronan to the enzyme. |
==About this Structure== | ==About this Structure== | ||
| - | 1LXK is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Streptococcus_pneumoniae Streptococcus pneumoniae]. Active as [http://en.wikipedia.org/wiki/Hyaluronate_lyase Hyaluronate lyase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=4.2.2.1 4.2.2.1] Full crystallographic information is available from [http:// | + | 1LXK is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Streptococcus_pneumoniae Streptococcus pneumoniae]. Active as [http://en.wikipedia.org/wiki/Hyaluronate_lyase Hyaluronate lyase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=4.2.2.1 4.2.2.1] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1LXK OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Streptococcus pneumoniae]] | [[Category: Streptococcus pneumoniae]] | ||
| - | [[Category: Groot, B | + | [[Category: Groot, B L.De.]] |
| - | [[Category: Jedrzejas, M | + | [[Category: Jedrzejas, M J.]] |
[[Category: Li, S.]] | [[Category: Li, S.]] | ||
| - | [[Category: Mello, L | + | [[Category: Mello, L V.]] |
[[Category: protein-carbohydrate complex]] | [[Category: protein-carbohydrate complex]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 13:49:24 2008'' |
Revision as of 11:49, 21 February 2008
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Streptococcus pneumoniae Hyaluronate Lyase in Complex with Tetrasaccharide Hyaluronan Substrate
Overview
Hyaluronate lyase enzymes degrade hyaluronan, the main polysaccharide component of the host connective tissues, predominantly into unsaturated disaccharide units, thereby destroying the normal connective tissue structure and exposing the tissue cells to various endo- and exogenous factors, including bacterial toxins. The crystal structures of Streptococcus pneumoniae hyaluronate lyase with tetra- and hexasaccharide hyaluronan substrates bound in the active site were determined at 1.52- and 2.0-A resolution, respectively. Hexasaccharide is the longest substrate segment that binds entirely within the active site of these enzymes. The enzyme residues responsible for substrate binding, positioning, catalysis, and product release were thereby identified and their specific roles characterized. The involvement of three residues in catalysis, Asn(349), His(399), and Tyr(408), is confirmed, and the details of proton acceptance and donation within the catalytic machinery are described. The mechanism of processivity of the enzyme is analyzed. The flexibility (allosteric) behavior of the enzyme may be understood in terms of the results of flexibility analysis of this protein, which identified two modes of motion that are also proposed to be involved in the hyaluronan degradation process. The first motion describes an opening and closing of the catalytic cleft located between the alpha- and beta-domains. The second motion demonstrates the mobility of a binding cleft, which may facilitate the binding of the negatively charged hyaluronan to the enzyme.
About this Structure
1LXK is a Single protein structure of sequence from Streptococcus pneumoniae. Active as Hyaluronate lyase, with EC number 4.2.2.1 Full crystallographic information is available from OCA.
Reference
Mechanism of hyaluronan degradation by Streptococcus pneumoniae hyaluronate lyase. Structures of complexes with the substrate., Jedrzejas MJ, Mello LV, de Groot BL, Li S, J Biol Chem. 2002 Aug 2;277(31):28287-97. Epub 2002 May 3. PMID:11991948
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