Improved the expression level of active transglutaminase by directional increasing copy of mtg gene in Pichia pastoris

摘要

BackgroundThe microbial transglutaminase (MTG) is inactive when only the mature sequence is expressed in Pichia pastoris. Although co-expression of MTG and its N-terminal pro-peptide can obtain the active MTG, the enzyme activity was still low. One of the basic steps for strain improvement is to ensure a sufficient level of transcription of the heterologous gene, based on promoter strength and gene copy number. To date, high-copy-number recombinants of P. pastoris are achievable only by cloning of gene concatemers, so methods for rapid and reliable multicopy strains are therefore desirable.