A Meiothermus strain capable of using β‐phenylalanine for growth is isolated by culture enrichment of samples collected in hot environments and the genome is sequenced showing the presence of 22 putative transaminase (TA) sequences. On the basis of phylogenetic and sequence analysis, a TA termed Ms‐TA2 is selected for further studies. The enzyme is successfully produced in Escherichia coli Rosetta(DE3) cells, with 70 mg of pure protein obtained from 1 L culture after purification by affinity chromatography. Ms‐TA2 shows high activity toward (S)‐β‐phenylalanine and other (S)‐β‐amino acids, as well as a preference for α‐ketoglutarate and aromatic aldehydes as amino acceptors. Moreover, Ms‐TA2 is shown to be a thermostable enzyme by maintaining about 60% of the starting activity after 3 h incubation at 50 °C and showing a melting temperature of about 73 °C. Finally, a homology‐based structural model of Ms‐TA2 is built and key active site interactions for substrate and cofactor binding are analyzed.

中文翻译：

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从冰岛温泉中分离出的Meiothermus菌株中发现一种新型的热稳定β-氨基酸转氨酶并进行表征。

通过富集在炎热环境中收集的样品来分离能够利用β-苯丙氨酸生长的Meiothermus菌株，并对基因组进行测序，显示存在22个假定的转氨酶（TA）序列。在系统发育和序列分析的基础上，选择了称为Ms-TA2的TA进行进一步研究。该酶在大肠杆菌Rosetta（DE3）细胞中成功产生，通过亲和层析纯化后，从1 L培养物中获得70 mg纯蛋白。Ms-TA2对（S）-β-苯丙氨酸和其他（S）-β-氨基酸，以及优先选择α-酮戊二酸酯和芳香醛作为氨基受体。此外，通过在50°C下孵育3小时后保持约60％的起始活性，Ms-TA2被证明是一种热稳定酶，其熔融温度约为73°C。最后，建立了基于同源性的Ms-TA2结构模型，并分析了底物和辅因子结合的关键活性位点相互作用。