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| {{STRUCTURE_1dmh| PDB=1dmh | SCENE= }} | | {{STRUCTURE_1dmh| PDB=1dmh | SCENE= }} |
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| '''STRUCTURE OF CATECHOL 1,2-DIOXYGENASE FROM ACINETOBACTER SP. ADP1 WITH BOUND 4-METHYLCATECHOL'''
| | ===STRUCTURE OF CATECHOL 1,2-DIOXYGENASE FROM ACINETOBACTER SP. ADP1 WITH BOUND 4-METHYLCATECHOL=== |
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| ==Overview==
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| BACKGROUND: Intradiol dioxygenases catalyze the critical ring-cleavage step in the conversion of catecholate derivatives to citric acid cycle intermediates. Catechol 1,2-dioxygenases (1, 2-CTDs) have a rudimentary design structure - a homodimer with one catalytic non-heme ferric ion per monomer, that is (alphaFe(3+))(2). This is in contrast to the archetypical intradiol dioxygenase protocatechuate 3,4-dioxygenase (3,4-PCD), which forms more diverse oligomers, such as (alphabetaFe(3+))(2-12). RESULTS: The crystal structure of 1,2-CTD from Acinetobacter sp. ADP1 (Ac 1,2-CTD) was solved by single isomorphous replacement and refined to 2.0 A resolution. The structures of the enzyme complexed with catechol and 4-methylcatechol were also determined at resolutions of 1.9 A and 1.8 A, respectively. While the characteristics of the iron ligands are similar, Ac 1,2-CTD differs from 3,4-PCDs in that only one subunit is used to fashion each active-site cavity. In addition, a novel 'helical zipper', consisting of five N-terminal helices from each subunit, forms the molecular dimer axis. Two phospholipids were unexpectedly found to bind within an 8 x 35 A hydrophobic tunnel along this axis. CONCLUSIONS: The helical zipper domain of Ac 1, 2-CTD has no equivalent in other proteins of known structure. Sequence analysis suggests the domain is a common motif in all members of the 1,2-CTD family. Complexes with catechol and 4-methylcatechol are the highest resolution complex structures to date of an intradiol dioxygenase. Furthermore, they confirm several observations seen in 3,4-PCDs, including ligand displacement upon binding exogenous ligands. The structures presented here are the first of a new family of intradiol dioxygenases.
| | The line below this paragraph, {{ABSTRACT_PUBMED_10801478}}, adds the Publication Abstract to the page |
| | (as it appears on PubMed at http://www.pubmed.gov), where 10801478 is the PubMed ID number. |
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| | {{ABSTRACT_PUBMED_10801478}} |
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| ==About this Structure== | | ==About this Structure== |
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| [[Category: Metalloenzyme]] | | [[Category: Metalloenzyme]] |
| [[Category: Substrate]] | | [[Category: Substrate]] |
| ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 14:01:18 2008'' | | |
| | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Mon Jun 30 23:17:38 2008'' |