| Autor: |
Lara AR; Departamento de Procesos y Tecnología, Universidad Autónoma Metropolitana-Cuajimalpa . Av. Vasco de Quiroga 4871, Santa Fe, C.P. 05348, Mexico City, México., Jaén KE; Departamento de Procesos y Tecnología, Universidad Autónoma Metropolitana-Cuajimalpa . Av. Vasco de Quiroga 4871, Santa Fe, C.P. 05348, Mexico City, México., Sigala JC; Departamento de Procesos y Tecnología, Universidad Autónoma Metropolitana-Cuajimalpa . Av. Vasco de Quiroga 4871, Santa Fe, C.P. 05348, Mexico City, México., Mühlmann M; RWTH Aachen University , AVT - Biochemical Engineering, Worringer Weg 1, 52074 Aachen, Germany., Regestein L; RWTH Aachen University , AVT - Biochemical Engineering, Worringer Weg 1, 52074 Aachen, Germany., Büchs J; RWTH Aachen University , AVT - Biochemical Engineering, Worringer Weg 1, 52074 Aachen, Germany. |
| Abstrakt: |
Oxygen limitation can be used as a simple environmental inducer for the expression of target genes. However, there is scarce information on the characteristics of microaerobic promoters potentially useful for cell engineering and synthetic biology applications. Here, we characterized the Vitreoscilla hemoglobin promoter (P vgb ) and a set of microaerobic endogenous promoters in Escherichia coli. Oxygen-limited cultures at different maximum oxygen transfer rates were carried out. The FMN-binding fluorescent protein (FbFP), which is a nonoxygen dependent marker protein, was used as a reporter. Fluorescence and fluorescence emission rates under oxygen-limited conditions were the highest when FbFP was under transcriptional control of P adhE , P pfl and P vgb . The lengths of the E. coli endogenous promoters were shortened by 60%, maintaining their key regulatory elements. This resulted in improved promoter activity in most cases, particularly for P adhE , P pfl and P narK . Selected promoters were also evaluated using an engineered E. coli strain expressing Vitreoscilla hemoglobin (VHb). The presence of the VHb resulted in a better repression using these promoters under aerobic conditions, and increased the specific growth and fluorescence emission rates under oxygen-limited conditions. These results are useful for the selection of promoters for specific applications and for the design of modified artificial promoters. |
