ISSN:
1432-0614
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Process Engineering, Biotechnology, Nutrition Technology
Notes:
Abstract A 63-base-pair synthetic promoter, sP1, was synthesized on the basis of the nucleotide sequence of a putative Streptococcus thermophilus promoter. When inserted upstream from the Streptomyces cho operon in a recombinant plasmid, pUCO195P-36, sP1 activated the expression of the cho genes in Escherichia coli, as shown by the production of cholesterol oxidase by the transformants. The sP1-driven cholesterol oxidase production in pUCO195P-36-transformed cells was estimated to be 40% of that produced by P lac -mediated cho expression in a pUCO193-containing host. The recombinant pUCO195P-36 appeared to be segregationally less stable in E. coli DH5α than in HB101. Its non-expressing counterpart, pUCO195P-1, was stable in both E. coli strains. The activity of sP1 was further demonstrated in E. coli by the expression of a Streptomyces melC operon. When placed upstream from the test operon in the pMCU22aPa construct, sP1 activated the melC expression as shown by the production of tyrosinase at (3.0±0.3)×10–3 U/mg and (16.0±1.0)×10–3 U/mg protein equivalent of cell extract in the absence and presence of isopropyl β-d-thiogalactopyranoside, respectively. The presence of a counter-oriented P lac at the 3' end of the operon in the pMCU22bPa plasmid reduced the sP1-mediated tyrosinase production by about 85%.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s002530050404
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