1dlq
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STRUCTURE OF CATECHOL 1,2-DIOXYGENASE FROM ACINETOBACTER SP. ADP1 INHIBITED BY BOUND MERCURY
OverviewOverview
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.
About this StructureAbout this Structure
1DLQ is a Single protein structure of sequence from Acinetobacter sp. with FE, HG and LIO as ligands. Active as Catechol 1,2-dioxygenase, with EC number 1.13.11.1 Full crystallographic information is available from OCA.
ReferenceReference
The 1.8 A crystal structure of catechol 1,2-dioxygenase reveals a novel hydrophobic helical zipper as a subunit linker., Vetting MW, Ohlendorf DH, Structure. 2000 Apr 15;8(4):429-40. PMID:10801478
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