1-aminocyclopropane-1-carboxylatedeaminases from aerobic methylotrophs: biochemical and phylogenetic aspects

The 1-aminocyclopropane-1-carboxylate (ACC) deaminases, the key enzymes of degradation of the precursor of the phytohormone ethylene, and have been poorly studied despite their great importance for plant-bacterial interactions. Last time there is an opinion, H₂S takes important part in growth and development regulation of plants and stress answer. However, molecular mechanisms of H₂S action in plants are poorly understood, although it is clear that key enzymes for hydrogen sulfide biosynthesis are D-cysteindesulfhydrases. Studied the spread of gene acdS and dcyD, which code key enzymes for increasing plants stability by bacteria, ACC-deaminase and D-cysteinesulfohydrase of aerobic methylotrophs genus Methylobacterium. And characterized ACC-deaminase from facultative methylotrophic actinomycetes Amycolatopsis methanolica 239. In result of research there were detected and sequenced genes acdS from Methylobacterium goesingense DSM21331 and dcyD from Methylobacterium trifolii DSM23632 and Methylobacterium gnaphalii 23e DSM 24027, and also constructed phylogenetic tree which was based on the translated amino acid sequence of proteins. For the first time ACC-deaminase was cloned and characterized from bacteria of phyllum Actinobcteria A.methanolica 239, what says about her supposed ability to be in simbiosys with plants. The enzyme had K_m 1.7 ± 0.2 mM. The k_cat values were 5,1±0,2 min^-1. AcdS is homotetramer with a molecular mass of 144 kDa. The purified enzyme displayed the maximum activity at 60 °C and pH 8.5. Results can be used for next researches of metabolic foundations plant-bacterial interactions.

1-аминоциклопропан-1-карбоксилатдезаминаза, Methylobacterium, Amycolatopsis methanolica 239, D-цистеин-десульфогидраза, aerobic methylotroph, 1-aminocylopropane-1-carboxylate deaminase, Methylobacterium, Amycolatopsis methanolica 239, D-cysteine desulfhydrase, plant-bacterial interactions

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