Review 2: Structures of an extradiol catechol dioxygenase- C23O64, from 3-nitrotoluene degrading Diaphorobacter sp. strain DS2 in substrate-free, substrate-bound and substrate analog-bound states

AbstractThis manuscript reports structure–function studies of Catechol 2,3-dioxygenase (C23O64), which is the second enzyme in the metabolic degradation pathway of 3-nitrotoluene by Diaphorobacter sp. strain DS2. The recombinant protein is a ring cleavage enzyme for 3-methylcatechol and 4-methylcatechol products formed after dioxygenation of the aromatic ring. Here we report the substrate-free, substrate-bound, and substrate-analog bound crystal structures of C23O64. The protein crystallizes in the P6(2)22 space-group. The structures were determined by molecular replacement and refined to resolutions of 2.4, 2.4, 2.2 Å, respectively. A comparison of the structures with related extradiol dioxygenases showed 22 conserved residues. A comparison of the active site pocket with catechol 2,3-dioxygenase (LapB) from Pseudomonas sp KL28 and homoprotocatechuate 2,3-dioxygenase (HPCD) from Brevibacterium fuscum shows significant similarities to suggest that the mechanism of enzyme action is similar to HPCD.

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Recent Radiative and Collisional Atomic Data of Astrophysical Interest

International Astronomical Union Colloquium ◽

10.1017/s0252921100107596 ◽

1988 ◽

Vol 102 ◽

pp. 129-132

Author(s):

K.L. Baluja ◽

K. Butler ◽

J. Le Bourlot ◽

C.J. Zeippen

Keyword(s):

Mass Production ◽

Bound States ◽

Physical Models ◽

Impact Excitation ◽

Electron Impact Excitation ◽

Atomic Data ◽

Isoelectronic Sequence ◽

Astrophysical Interest ◽

Radiative Transitions ◽

Forbidden Transitions

SummaryUsing sophisticated computer programs and elaborate physical models, accurate radiative and collisional atomic data of astrophysical interest have been or are being calculated. The cases treated include radiative transitions between bound states in the 2p4and 2s2p5configurations of many ions in the oxygen isoelectronic sequence, the photoionisation of the ground state of neutral iron, the electron impact excitation of the fine-structure forbidden transitions within the 3p3ground configuration of CℓIII, Ar IV and K V, and the mass-production of radiative data for ions in the oxygen and fluorine isoelectronic sequences, as part of the international Opacity Project.

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