1b9i
From Proteopedia
(New page: 200px<br /><applet load="1b9i" size="450" color="white" frame="true" align="right" spinBox="true" caption="1b9i, resolution 2.0Å" /> '''CRYSTAL STRUCTURE OF ...) |
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| - | [[Image:1b9i.jpg|left|200px]]<br /><applet load="1b9i" size=" | + | [[Image:1b9i.jpg|left|200px]]<br /><applet load="1b9i" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1b9i, resolution 2.0Å" /> | caption="1b9i, resolution 2.0Å" /> | ||
'''CRYSTAL STRUCTURE OF 3-AMINO-5-HYDROXYBENZOIC ACID (AHBA) SYNTHASE'''<br /> | '''CRYSTAL STRUCTURE OF 3-AMINO-5-HYDROXYBENZOIC ACID (AHBA) SYNTHASE'''<br /> | ||
==Overview== | ==Overview== | ||
| - | The biosynthesis of ansamycin antibiotics, including rifamycin B, involves | + | The biosynthesis of ansamycin antibiotics, including rifamycin B, involves the synthesis of an aromatic precursor, 3-amino-5-hydroxybenzoic acid (AHBA), which serves as starter for the assembly of the antibiotics' polyketide backbone. The terminal enzyme of AHBA formation, AHBA synthase, is a dimeric, pyridoxal 5'-phosphate (PLP) dependent enzyme with pronounced sequence homology to a number of PLP enzymes involved in the biosynthesis of antibiotic sugar moieties. The structure of AHBA synthase from Amycolatopsis mediterranei has been determined to 2.0 A resolution, with bound cofactor, PLP, and in a complex with PLP and an inhibitor (gabaculine). The overall fold of AHBA synthase is similar to that of the aspartate aminotransferase family of PLP-dependent enzymes, with a large domain containing a seven-stranded beta-sheet surrounded by alpha-helices and a smaller domain consisting of a four-stranded antiparallel beta-sheet and four alpha-helices. The uninhibited form of the enzyme shows the cofactor covalently linked to Lys188 in an internal aldimine linkage. On binding the inhibitor, gabaculine, the internal aldimine linkage is broken, and a covalent bond is observed between the cofactor and inhibitor. The active site is composed of residues from two subunits of AHBA synthase, indicating that AHBA synthase is active as a dimer. |
==About this Structure== | ==About this Structure== | ||
| - | 1B9I is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Amycolatopsis_mediterranei Amycolatopsis mediterranei] with PXG as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http:// | + | 1B9I is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Amycolatopsis_mediterranei Amycolatopsis mediterranei] with <scene name='pdbligand=PXG:'>PXG</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1B9I OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Beeby, M.]] | [[Category: Beeby, M.]] | ||
| - | [[Category: Eads, J | + | [[Category: Eads, J C.]] |
| - | [[Category: Floss, H | + | [[Category: Floss, H G.]] |
[[Category: Scapin, G.]] | [[Category: Scapin, G.]] | ||
| - | [[Category: Yu, T | + | [[Category: Yu, T W.]] |
[[Category: PXG]] | [[Category: PXG]] | ||
[[Category: rifamycin biosynthesis (rifd gene)]] | [[Category: rifamycin biosynthesis (rifd gene)]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 11:52:55 2008'' |
Revision as of 09:52, 21 February 2008
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CRYSTAL STRUCTURE OF 3-AMINO-5-HYDROXYBENZOIC ACID (AHBA) SYNTHASE
Overview
The biosynthesis of ansamycin antibiotics, including rifamycin B, involves the synthesis of an aromatic precursor, 3-amino-5-hydroxybenzoic acid (AHBA), which serves as starter for the assembly of the antibiotics' polyketide backbone. The terminal enzyme of AHBA formation, AHBA synthase, is a dimeric, pyridoxal 5'-phosphate (PLP) dependent enzyme with pronounced sequence homology to a number of PLP enzymes involved in the biosynthesis of antibiotic sugar moieties. The structure of AHBA synthase from Amycolatopsis mediterranei has been determined to 2.0 A resolution, with bound cofactor, PLP, and in a complex with PLP and an inhibitor (gabaculine). The overall fold of AHBA synthase is similar to that of the aspartate aminotransferase family of PLP-dependent enzymes, with a large domain containing a seven-stranded beta-sheet surrounded by alpha-helices and a smaller domain consisting of a four-stranded antiparallel beta-sheet and four alpha-helices. The uninhibited form of the enzyme shows the cofactor covalently linked to Lys188 in an internal aldimine linkage. On binding the inhibitor, gabaculine, the internal aldimine linkage is broken, and a covalent bond is observed between the cofactor and inhibitor. The active site is composed of residues from two subunits of AHBA synthase, indicating that AHBA synthase is active as a dimer.
About this Structure
1B9I is a Single protein structure of sequence from Amycolatopsis mediterranei with as ligand. Full crystallographic information is available from OCA.
Reference
Crystal structure of 3-amino-5-hydroxybenzoic acid (AHBA) synthase., Eads JC, Beeby M, Scapin G, Yu TW, Floss HG, Biochemistry. 1999 Aug 3;38(31):9840-9. PMID:10433690
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