|
type |
Journal Article |
authors |
Fedorov DN1, Ekimova GA, Doronina NV, Trotsenko YA. |
title |
1-Aminocyclopropane-1-carboxylate (ACC) deaminases from Methylobacterium radiotolerans and Methylobacterium nodulans with higher specificity for ACC |
journal |
FEMS Microbiol Lett |
Activity |
3.5.99.7 |
Family |
3.5.99.7 |
sel |
selected |
ui |
23517598 |
year |
(2013) |
volume |
343 |
number |
1 |
pages |
70-6 |
| |
abstract |
The 1-aminocyclopropane-1-carboxylate (ACC) deaminases (EC 3.4.99.7), the key enzymes of degradation of the precursor of the phytohormone ethylene, have not been well studied despite their great importance for plant-bacterial interactions. Using blast, the open reading frames encoding ACC deaminases were found in the genomes of epiphytic methylotroph Methylobacterium radiotolerans JCM2831 and nodule-forming endosymbiont Methylobacterium nodulans ORS2060. These genes were named acdS and cloned; recombinant proteins were expressed and purified from Escherichia coli. The enzyme from M. nodulans displayed the highest substrate specificity among all of the characterized ACC deaminases (Km 0.80 ± 0.04 mM), whereas the enzyme from M. radiotolerans had Km 1.8 ± 0.3 mM. The kcat values were 111.8 ± 0.2 and 65.8 ± 2.8 min(-1) for the enzymes of M. nodulans and M. radiotolerans, respectively. Both enzymes are homotetramers with a molecular mass of 144 kDa, as was demonstrated by size exclusion chromatography and native PAGE. The purified enzymes displayed the maximum activity at 45-50 °C and pH 8.0. Thus, the priority data have been obtained, extending the knowledge of biochemical properties of bacterial ACC deaminases. |
fulltext |
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last changed |
2018/05/07 13:17 |
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