Format:
Illustrationen
ISSN:
2076-2607
Content:
Despite several discoveries in recent years, the physiology of acidophilic Micrarchaeota, such as “Candidatus Micrarchaeum harzensis A_DKE”, remains largely enigmatic, as they highly express numerous genes encoding hypothetical proteins. Due to a lacking genetic system, it is difficult to elucidate the biological function of the corresponding proteins and heterologous expression is required. In order to prove the viability of this approach, A_DKE’s isocitrate dehydrogenase (MhIDH) was recombinantly produced in Escherichia coli and purified to electrophoretic homogeneity for biochemical characterization. MhIDH showed optimal activity around pH 8 and appeared to be specific for NADP+ yet promiscuous regarding divalent cations as cofactors. Kinetic studies showed KM-values of 53.03 _ 5.63 _Mand 1.94 _ 0.12mMand kcat-values of 38.48 _ 1.62 and 43.99 _ 1.46 s1 resulting in kcat/KM-values of 725 _ 107.62 and 22.69 _ 2.15 mM1 s1 for DL-isocitrate and NADP+, respectively. MhIDH’s exceptionally low affinity for NADP+, potentially limiting its reaction rate, can likely be attributed to the presence of a proline residue in the NADP+ binding pocket, which might cause a decrease in hydrogen bonding of the cofactor and a distortion of local secondary structure.
Note:
Sonstige Körperschaft: Technische Universität Hamburg
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Sonstige Körperschaft: Technische Universität Hamburg, Institut für Technische Mikrobiologie
In:
Microorganisms, Basel : MDPI, 2013, 9(2021), 11 vom: 9. Nov., Artikel-ID 2318, Seite 1-16, 2076-2607
In:
volume:9
In:
year:2021
In:
number:11
In:
day:9
In:
month:11
In:
elocationid:2318
In:
pages:1-16
Language:
English
DOI:
10.3390/microorganisms9112318
URN:
urn:nbn:de:gbv:830-882.0158224
URL:
https://doi.org/10.3390/microorganisms9112318
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