1m6s: Difference between revisions
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New page: left|200px<br /><applet load="1m6s" size="450" color="white" frame="true" align="right" spinBox="true" caption="1m6s, resolution 1.8Å" /> '''Crystal Structure Of ... |
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[[Image:1m6s.jpg|left|200px]]<br /><applet load="1m6s" size=" | [[Image:1m6s.jpg|left|200px]]<br /><applet load="1m6s" size="350" color="white" frame="true" align="right" spinBox="true" | ||
caption="1m6s, resolution 1.8Å" /> | caption="1m6s, resolution 1.8Å" /> | ||
'''Crystal Structure Of Threonine Aldolase'''<br /> | '''Crystal Structure Of Threonine Aldolase'''<br /> | ||
==Overview== | ==Overview== | ||
L-Threonine acetaldehyde-lyase (threonine aldolase, TA) is a | L-Threonine acetaldehyde-lyase (threonine aldolase, TA) is a pyridoxal-5'-phosphate-dependent (PLP) enzyme that catalyzes conversion of L-threonine or L-allo-threonine to glycine and acetaldehyde in a secondary glycine biosynthetic pathway. X-ray structures of Thermatoga maritima TA have been determined as the apo-enzyme at 1.8 A resolution and bound to substrate L-allo-threonine and product glycine at 1.9 and 2.0 A resolution, respectively. Despite low pairwise sequence identities, TA is a member of aspartate aminotransferase (AATase) fold family of PLP enzymes. The enzyme forms a 222 homotetramer with the PLP cofactor bound via a Schiff-base linkage to Lys199 within a domain interface. The structure reveals bound calcium and chloride ions that appear to contribute to catalysis and oligomerization, respectively. Although L-threonine and L-allo-threonine are substrates for T. maritima TA, enzymatic assays revealed a strong preference for L-allo-threonine. Structures of the external aldimines with substrate/product reveal a pair of histidines that may provide flexibility in substrate recognition. Variation in the threonine binding pocket may explain preferences for L-allo-threonine versus L-threonine among TA family members. | ||
==About this Structure== | ==About this Structure== | ||
1M6S is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Thermotoga_maritima Thermotoga maritima] with CA and CL as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Threonine_aldolase Threonine aldolase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=4.1.2.5 4.1.2.5] Full crystallographic information is available from [http:// | 1M6S is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Thermotoga_maritima Thermotoga maritima] with <scene name='pdbligand=CA:'>CA</scene> and <scene name='pdbligand=CL:'>CL</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Threonine_aldolase Threonine aldolase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=4.1.2.5 4.1.2.5] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1M6S OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: Thermotoga maritima]] | [[Category: Thermotoga maritima]] | ||
[[Category: Threonine aldolase]] | [[Category: Threonine aldolase]] | ||
[[Category: Burley, S | [[Category: Burley, S K.]] | ||
[[Category: Kielkopf, C | [[Category: Kielkopf, C L.]] | ||
[[Category: CA]] | [[Category: CA]] | ||
[[Category: CL]] | [[Category: CL]] | ||
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[[Category: vitamin b12]] | [[Category: vitamin b12]] | ||
''Page seeded by [http:// | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 13:52:07 2008'' | ||
