Abstract: Several endogenous 5′UTRs (5′-untranslated region) and their downstream sequences with highest protein abundance were firstly identified from the genome of Corynebacterium glutamicum CGMCC1.15647, and these 5′UTRs and their downstream sequences with two strong promoters PH36 and Ptacwere used to construct monocistronic (MEM) and bicistronic expression model (BEM). In both MEM and BEM, the 5′UTR and its downstream sequence significantly enhanced the expression ability of these promoters. Among them, the highest expression intensity of these vector, pTac-B2826-EGFP, was about 3.6 times that of the positive expression vector pTac-Positive. Several vectors with high expression ability were selected to express the variable domain of heavy chain of heavy-chain antibody (VHH) protein in Corynebacterium glutamicum. In the shake flask fermentation culture, the secreted expression of the protein VHH reached 85.4 mg/L. All these works provided several new vectors with strong expression ability for heterologous protein expression of Corynebacterium glutamicum.

Key words: Corynebacterium glutamicum, 5′UTR, BEM, VHH