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Charakterisierung der reduktiven Aktivitäten der CO-Dehydrogenasen aus Oligotropha carboxidovorans und Streptomyces thermoautotrophicus

URN to cite this document: urn:nbn:de:bvb:703-opus-1008

Title data

Sarjiya, Antonius:
Charakterisierung der reduktiven Aktivitäten der CO-Dehydrogenasen aus Oligotropha carboxidovorans und Streptomyces thermoautotrophicus.
Bayreuth , 2004
( Doctoral thesis, 2004 , University of Bayreuth, Faculty of Biology, Chemistry and Earth Sciences)

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Abstract

Es wurde in dieser Arbeit entdeckt, dass die aerobe CO-Dehydrogenase in der Lage ist, alternative Substrate wie Azid, Nitrit und Nitrat zu reduzieren. CO-Dehydrogenase aus Oligotropha carboxidovorans und Streptomyces thermoautotrophicus führen die Reduktionsreaktion wie folgt durch: Azid wird zu Ammonium und molekularem Distickstoff reduziert. N3- + 2 e- + 3 H+ -> NH3 + N2 Nitrit wird zu Ammonium reduziert. NO2- + 6 e- + 7 H+ -> NH3 + 2H2O Nitrat wird zu Nitrit reduziert. NO3- + 2H+ + 2e- -> NO2- + H2O Das katalytische [CuSMoO2]-Zentrum der CO-Dehydrogenase ist verantwortlich für die Reduktion von Azid und Nitrit. Ohne einem aktiven katalytischen-Zentrum findet die Reduktion von Azid und Nitrit nicht statt. Die CO-Dehydrogenase katalysiert gleichzeitig die H2-Oxidation und die Azid-Reduktion. Die während der H2-Oxidation entstehenden Elektronen werden für die Azid-Reduktion verwendet. H2 + N3- + H+ -> NH3 + N2 Oxidation und Reduktion finden mit größter Wahrscheinlichkeit am katalytisch aktiven [CuSMoO2]-Cluster der CO-Dehydrogenase statt. Die gleichzeitige Anwesenheit von CO und Azid hemmt die CO-Oxidations- und Azid-Reduktionsaktivität. Die Kristallstruktur zeigt, dass in Gegenwart von CO und Azid aus dem [CuSMoO2]-Cluster das Cu-Atom und der Sulfidoligand entfernt sind. Die Nitrat-Reduktion der CO-Dehydrogenase ist unabhängig vom katalytisch aktiven [CuSMoO2]-Cluster. Die CO-Dehydrogenase aus S. thermoautotrophicus zeigt ähnliche Oxidations- und Reduktionsaktivitäten. Die CO-Dehydrogenase aus dem thermophilen, Gram-positiven Bakterium S. thermoautotrophicus reagiert sehr ähnlich wie die CO-Dehydrogenase aus dem mesophilen, Gram-neagtiven Bakterium O. carboxidovorans.

Abstract in another language

In this work it has been discovered that the aerobic CO dehydrogenase is able to reduce alternative substrates such as azide, nitrite and nitrate. CO dehydrogenases from Oligotropha carboxidovorans and Streptomyces thermoautotrophicus reduce the above mentioned substrates according to following equations: Azide was reduced to ammonium and molecular dinitrogen (N2): N3- + 2 e- + 3 H+ -> NH3 + N2 Nitrite was reduced to ammonium NO2- + 6 e- + 7 H+ -> NH3 + 2H2O Nitrate was reduced to nitrite: NO3- + 2H+ + 2e- -> NO2- + H2O The catalytic active site [CuSMoO2]-cluster present in CO dehydrogenase is responsible for the reduction of azide and nitrite. Azide and nitrite reduction did not take place without an active catalytic cluster. The reduction of azide and nitrite are closely correlated to the oxidation of CO. CO dehydrogenase catalyses simultaneously the oxidation of H2 and the reduction of azide. The electrons liberated during H2 oxidation were used to reduce azide. H2 + N3- + H+ -> NH3 + N2 Oxidation and reduction activities most probably take place at the active site of the [CuSMoO2]-cluster of CO dehydrogenase. The presence of CO and azide together causes inhibition of the CO oxidation and azide reduction completely. The crystal structure reveals that in the presence of CO and azide the Cu-atom and sulfido ligand are removed from the [CuSMoO2]-cluster. Nitrate reduction is not dependent on the [CuSMoO2]-cluster. In the absence of [CuSMoO2]-cluster or in the case of damaged [CuSMoO2]-cluster nitrate was reduced to ammonium. Die CO dehydrogenase from S. thermoautotrophicus shows similar oxidation and reduction activities. CO dehydrogenase from the thermophilic, gram positive bacterium S. thermoautotrophicus is very similar to CO dehydrogenase from the mesohilic gram negative bacterium O. carboxidovorans.

Further data

Item Type: Doctoral thesis (No information)
Keywords: Kohlenmonoxid-Dehydrogenase; Streptomyces thermoautotrophicus; Pseudomonas carboxydovorans; Azide; Cyanid; Ammonium; Reduktion; Streptomyces thermoautotrophicus; Pseudomonas carboxydovorans; CO dehydrogenases
DDC Subjects: 500 Science > 570 Life sciences, biology
Institutions of the University: Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Biology
Faculties
Faculties > Faculty of Biology, Chemistry and Earth Sciences
Language: German
Originates at UBT: Yes
URN: urn:nbn:de:bvb:703-opus-1008
Date Deposited: 26 Apr 2014 13:16
Last Modified: 26 Apr 2014 13:16
URI: https://epub.uni-bayreuth.de/id/eprint/935

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