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| - | [[Image:1yrl.gif|left|200px]] | + | {{Seed}} |
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| | {{STRUCTURE_1yrl| PDB=1yrl | SCENE= }} | | {{STRUCTURE_1yrl| PDB=1yrl | SCENE= }} |
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| - | '''Escherichia coli ketol-acid reductoisomerase'''
| + | ===Escherichia coli ketol-acid reductoisomerase=== |
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| - | ==Overview==
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| - | Ketol-acid reductoisomerase (KARI; EC 1.1.1.86) catalyzes two steps in the biosynthesis of branched-chain amino acids. Amino acid sequence comparisons across species reveal that there are two types of this enzyme: a short form (Class I) found in fungi and most bacteria, and a long form (Class II) typical of plants. Crystal structures of each have been reported previously. However, some bacteria such as Escherichia coli possess a long form, where the amino acid sequence differs appreciably from that found in plants. Here, we report the crystal structure of the E. coli enzyme at 2.6 A resolution, the first three-dimensional structure of any bacterial Class II KARI. The enzyme consists of two domains, one with mixed alpha/beta structure, which is similar to that found in other pyridine nucleotide-dependent dehydrogenases. The second domain is mainly alpha-helical and shows strong evidence of internal duplication. Comparison of the active sites between KARI of E. coli, Pseudomonas aeruginosa, and spinach shows that most residues occupy conserved positions in the active site. E. coli KARI was crystallized as a tetramer, the likely biologically active unit. This contrasts with P. aeruginosa KARI, which forms a dodecamer, and spinach KARI, a dimer. In the E. coli KARI tetramer, a novel subunit-to-subunit interacting surface is formed by a symmetrical pair of bulbous protrusions.
| + | The line below this paragraph, {{ABSTRACT_PUBMED_16322583}}, adds the Publication Abstract to the page |
| | + | (as it appears on PubMed at http://www.pubmed.gov), where 16322583 is the PubMed ID number. |
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| | + | {{ABSTRACT_PUBMED_16322583}} |
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| | ==About this Structure== | | ==About this Structure== |
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| | [[Category: Knotted protein]] | | [[Category: Knotted protein]] |
| | [[Category: Reductoisomerase]] | | [[Category: Reductoisomerase]] |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 16:41:39 2008'' | + | |
| | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Tue Jul 29 04:53:37 2008'' |
Revision as of 01:53, 29 July 2008
Template:STRUCTURE 1yrl
Escherichia coli ketol-acid reductoisomerase
Template:ABSTRACT PUBMED 16322583
About this Structure
1YRL is a Single protein structure of sequence from Escherichia coli. Full crystallographic information is available from OCA.
Reference
The crystal structure of a bacterial class II ketol-acid reductoisomerase: domain conservation and evolution., Tyagi R, Duquerroy S, Navaza J, Guddat LW, Duggleby RG, Protein Sci. 2005 Dec;14(12):3089-100. PMID:16322583
Page seeded by OCA on Tue Jul 29 04:53:37 2008
