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Publication Abstract from PubMed

The identification and 3D structural characterization of a homolog of the (R)-selective transaminase (RTA) from Aspergillus terreus (AtRTA), from the thermotolerant fungus Thermomyces stellatus (TsRTA) is here reported. The thermostability of TsRTA (40% retained activity after 7 days at 40 degrees C) was initially attributed to its tetrameric form in solution, however subsequent studies of AtRTA revealed it also exists predominantly as a tetramer yet, at 40 degrees C, it is inactivated within 48 h. The engineering of a cysteine residue to promote disulfide bond formation across the dimer-dimer interface stabilized both enzymes, with TsRTA_G205C retaining almost full activity after incubation at 50 degrees C for 7 days. Thus, the role of this mutation was elucidated and the importance of stabilizing the tetramer for overall stability of RTAs is highlighted. TsRTA accepts the common amine donors (R)-methylbenzylamine, isopropylamine, and d-alanine as well as aromatic and aliphatic ketones and aldehydes.

An (R)-Selective Transaminase From Thermomyces stellatus: Stabilizing the Tetrameric Form.,Heckmann CM, Gourlay LJ, Dominguez B, Paradisi F Front Bioeng Biotechnol. 2020 Jul 22;8:707. doi: 10.3389/fbioe.2020.00707., eCollection 2020. PMID:32793563^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.