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Spectroscopic and computational stud...

Pau, Monita Yuen-Ming.

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Spectroscopic and computational studies of the intradiol and extradiol dioxygenases: Understanding oxygen activation by ferrous and ferric non-heme iron active sites.

Record Type:	Language materials, printed : Monograph/item
Title/Author:	Spectroscopic and computational studies of the intradiol and extradiol dioxygenases: Understanding oxygen activation by ferrous and ferric non-heme iron active sites./
Author:	Pau, Monita Yuen-Ming.
Description:	196 p.
Notes:	Adviser: Edward I. Solomon.
Contained By:	Dissertation Abstracts International68-02B.
Subject:	Chemistry, Biochemistry. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3253524

Spectroscopic and computational studies of the intradiol and extradiol dioxygenases: Understanding oxygen activation by ferrous and ferric non-heme iron active sites.
Pau, Monita Yuen-Ming.

Spectroscopic and computational studies of the intradiol and extradiol dioxygenases: Understanding oxygen activation by ferrous and ferric non-heme iron active sites. - 196 p.

Adviser: Edward I. Solomon.

Thesis (Ph.D.)--Stanford University, 2007.

Mononuclear non-heme iron enzymes catalyze a wide range of biological reactions involving O2. A sub-class of these enzymes is the catechol dioxygenases. They are mostly found in soil bacteria but related enzymes are also found in humans. They catalyze the ring cleavage of catecholic substrates by inserting both atoms of O2 into the aromatic ring. Based on the position of ring cleavage, the catechol dioxygenases are further divided into intradiol and extradiol dioxygenases. These enzymes have different residues around the iron center and differ in metal oxidation states and reaction mechanisms. Intradiol dioxygenases employ a Fe3+ center to activate the substrate for direct attack by O2 and insert O2 between the vicinal hydroxyl groups to yield muconic acids derivatives. Alternatively, extradiol dioxygenases use a Fe2+ center to activate O 2 and incorporate both atoms of O2 adjacent to the vicinal diols to yield muconic semialdehyde products. The significance of these enzymes lies in their role in bioremediation, and mutations in human enzymes are associated with genetic diseases.Subjects--Topical Terms:

1017722
Chemistry, Biochemistry.

Spectroscopic and computational studies of the intradiol and extradiol dioxygenases: Understanding oxygen activation by ferrous and ferric non-heme iron active sites.
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035 $a (UMI)AAI3253524
035 $a AAI3253524
040 $a UMI $c UMI
100 1 $a Pau, Monita Yuen-Ming. $3 1263220
245 1 0 $a Spectroscopic and computational studies of the intradiol and extradiol dioxygenases: Understanding oxygen activation by ferrous and ferric non-heme iron active sites.
300 $a 196 p.
500 $a Adviser: Edward I. Solomon.
500 $a Source: Dissertation Abstracts International, Volume: 68-02, Section: B, page: 0966.
502 $a Thesis (Ph.D.)--Stanford University, 2007.
520 $a Mononuclear non-heme iron enzymes catalyze a wide range of biological reactions involving O2. A sub-class of these enzymes is the catechol dioxygenases. They are mostly found in soil bacteria but related enzymes are also found in humans. They catalyze the ring cleavage of catecholic substrates by inserting both atoms of O2 into the aromatic ring. Based on the position of ring cleavage, the catechol dioxygenases are further divided into intradiol and extradiol dioxygenases. These enzymes have different residues around the iron center and differ in metal oxidation states and reaction mechanisms. Intradiol dioxygenases employ a Fe3+ center to activate the substrate for direct attack by O2 and insert O2 between the vicinal hydroxyl groups to yield muconic acids derivatives. Alternatively, extradiol dioxygenases use a Fe2+ center to activate O 2 and incorporate both atoms of O2 adjacent to the vicinal diols to yield muconic semialdehyde products. The significance of these enzymes lies in their role in bioremediation, and mutations in human enzymes are associated with genetic diseases.
520 $a Oxygen intermediates are often too labile to be trapped for spectroscopic studies; therefore we applied a combination of experiments and theoretical calculations on a series of anaerobic species to evaluate the similarities and differences in these enzymes. To understand how the Fe3+ site activates the substrate in intradiol dioxygenases, we characterized the geometric and electronic structures of the anaerobic enzyme-substrate complex by using variable-temperature variable-field magnetic circular dichroism spectroscopy and density functional theory (DFT) calculations. We further developed a theoretical model to explain how triplet O2 interacts with singlet catechol in this formally spin-forbidden reaction. To understand how the Fe 2+ site activates O2 in extradiol dioxygenases, we used NO as an O2 analogue to study potential FeO2 intermediates in the protein-catalyzed reactions. We developed an experimentally calibrated DFT protocol for {FeNO}7 complexes using a well-characterized model system. By applying this DFT methodology on the enzyme-nitrosyl complexes and complementing the results by spectroscopic data, we have laid the foundation necessary for the investigation of the O2 reaction coordinate of extradiol dioxygenases and identification of factors governing the specificity of ring cleavage in the catechol dioxygenases.
590 $a School code: 0212.
650 4 $a Chemistry, Biochemistry. $3 1017722
650 4 $a Chemistry, Inorganic. $3 517253
650 4 $a Chemistry, Physical. $3 560527
690 $a 0487
690 $a 0488
690 $a 0494
710 2 $a Stanford University. $3 754827
773 0 $t Dissertation Abstracts International $g 68-02B.
790 $a 0212
790 1 0 $a Solomon, Edward I., $e advisor
791 $a Ph.D.
792 $a 2007
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3253524