Biochemical characterisation of four rhamnosidases from thermophilic bacteria of the genera Thermotoga, Caldicellulosiruptor and Thermoclostridium.

Autor: Baudrexl M; Technical University of Munich, Department of Microbiology, Emil-Ramann-Str. 4, 85354, Freising, Germany., Schwarz WH; Aspratis GmbH, Hübnerstr. 11, 80637, München, Germany., Zverlov VV; Technical University of Munich, Department of Microbiology, Emil-Ramann-Str. 4, 85354, Freising, Germany. vladimir.zverlov@tum.de.; Institute of Molecular Genetics, Russian Academy of Science, Kurchatov Sq. 2, 123182, Moscow, Russia. vladimir.zverlov@tum.de., Liebl W; Technical University of Munich, Department of Microbiology, Emil-Ramann-Str. 4, 85354, Freising, Germany. wliebl@wzw.tum.de.
Jazyk: angličtina
Zdroj: Scientific reports [Sci Rep] 2019 Nov 04; Vol. 9 (1), pp. 15924. Date of Electronic Publication: 2019 Nov 04.
DOI: 10.1038/s41598-019-52251-0
Abstrakt: Carbohydrate active enzymes are classified in databases based on sequence and structural similarity. However, their function can vary considerably within a similarity-based enzyme family, which makes biochemical characterisation indispensable to unravel their physiological role and to arrive at a meaningful annotation of the corresponding genes. In this study, we biochemically characterised the four related enzymes Tm_Ram106B, Tn_Ram106B, Cb_Ram106B and Ts_Ram106B from the thermophilic bacteria Thermotoga maritima MSB8, Thermotoga neapolitana Z2706-MC24, Caldicellulosiruptor bescii DSM 6725 and Thermoclostridium stercorarium DSM 8532, respectively, as α-L-rhamnosidases. Cobalt, nickel, manganese and magnesium ions stimulated while EDTA and EGTA inhibited all four enzymes. The kinetic parameters such as K m , V max and k cat were about average compared to other rhamnosidases. The enzymes were inhibited by rhamnose, with half-maximal inhibitory concentrations (IC 50 ) between 5 mM and 8 mM. The α-L-rhamnosidases removed the terminal rhamnose moiety from the rutinoside in naringin, a natural flavonone glycoside. The Thermotoga sp. enzymes displayed the highest optimum temperatures and thermostabilities of all rhamnosidases reported to date. The four thermophilic and divalent ion-dependent rhamnosidases are the first biochemically characterised orthologous enzymes recently assigned to glycoside hydrolase family 106.
Databáze: MEDLINE
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