Activation of Recombinantly Expressed l-Amino Acid Oxidase from Rhizoctonia solani by Sodium Dodecyl Sulfate

• Published in: Molecules (Basel, Switzerland) Vol. 22; no. 12; p. 2272
• Main Authors: Hahn, Katharina, Hertle, Yvonne, Bloess, Svenja, Kottke, Tilman, Hellweg, Thomas, Fischer von Mollard, Gabriele
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 20.12.2017; MDPI
• Subjects: ">l-amino acid oxidase; activation; active conformation; Adducts; Amino acid oxidase; Amino acids; Amino Acids - chemistry; Catalysis; Catalytic Domain; Chromatography; conformational change; Deamination; Detergents; Detergents - chemistry; Enzyme Activation; Enzymes; Fatty Acids - chemistry; Flavin-adenine dinucleotide; Fluorescence; Fusion protein; Hydrogen peroxide; Hydrophobic and Hydrophilic Interactions; Inactivation; L-Amino Acid Oxidase - chemistry; L-Amino Acid Oxidase - genetics; L-Amino Acid Oxidase - isolation & purification; Light scattering; Molecular structure; Oligomerization; Oxidation-Reduction; Photon correlation spectroscopy; photon correlation spectroscopy (PCS); Protein Conformation; Protein structure; Recombinant Fusion Proteins - chemistry; Recombinant Fusion Proteins - genetics; Recombinant Fusion Proteins - isolation & purification; Rhizoctonia - enzymology; Rhizoctonia solani; SDS; Size exclusion chromatography; Sodium; Sodium dodecyl sulfate; Sodium Dodecyl Sulfate - chemistry; Sulfates; Sulfites; Surface-Active Agents - chemistry; Tryptophan; photon correlation spectroscopy (PCS); active conformation; ">l-amino acid oxidase; SDS; activation; conformational change
• DOI: 10.3390/molecules22122272
• ISSN: 1420-3049

l-Amino acid oxidases (l-AAO) catalyze the oxidative deamination of l-amino acids to the corresponding α-keto acids. The non-covalently bound cofactor FAD is reoxidized by oxygen under formation of hydrogen peroxide. We expressed an active l-AAO from the fungus as a fusion protein in . Treatment with small amounts of the detergent sodium dodecyl sulfate (SDS) stimulated the activity of the enzyme strongly. Here, we investigated whether other detergents and amphiphilic molecules activate 9His- LAAO1. We found that 9His- LAAO1 was also activated by sodium tetradecyl sulfate. Other detergents and fatty acids were not effective. Moreover, effects of SDS on the oligomerization state and the protein structure were analyzed. Native and SDS-activated 9His- LAAO1 behaved as dimers by size-exclusion chromatography. SDS treatment induced an increase in hydrodynamic radius as observed by size-exclusion chromatography and dynamic light scattering. The activated enzyme showed accelerated thermal inactivation and an exposure of additional protease sites. Changes in tryptophan fluorescence point to a more hydrophilic environment. Moreover, FAD fluorescence increased and a lower concentration of sulfites was sufficient to form adducts with FAD. Taken together, these data point towards a more open conformation of SDS-activated l-amino acid oxidase facilitating access to the active site.