Effects of His-Tag Length on the Soluble Expression and Selective Immobilization of D-Amino Acid Oxidase from Trigonopsis variabilis: A Preliminary Study

His-tags are widely used for the purification of recombinant proteins. High-cost carriers functionalized with nickel ions commonly required selective immobilization His-tagged enzymes. In this study, varying lengths were fused to N-terminus D-amino acid oxidase (DAO) from Trigonopsis variabilis. The attachment a His6 tag significantly improved solubility DAO expressed in Escherichia coli. By modulating lengths, better balance between cell growth and protein was achieved, resulting higher volume activity (His3). Furthermore, fusion longer tags (His6 His9) facilitated rapid DAOs onto commercial epoxy carrier without metal bearing, more immobilization. conclusion, modulation His-tag length preliminarily demonstrated as simple cost-effective approach achieve efficient expression, well fast DAO.