title: Expression of the sweet-tasting plant protein brazzein in Escherichia coli and Lactococcus lactis: a path toward sweet lactic acid bacteria.
abstract: Brazzein is an intensely sweet-tasting plant protein with good stability, which makes it an attractive alternative to sucrose. A brazzein gene has been designed, synthesized, and expressed in Escherichia coli at 30 degrees C to yield brazzein in a soluble form and in considerable quantity. Antibodies have been produced using brazzein fused to His-tag. Brazzein without the tag was sweet and resembled closely the taste of its native counterpart. The brazzein gene was also expressed in Lactococcus lactis, using a nisin-controlled expression system, to produce sweet-tasting lactic acid bacteria. The low level of expression was detected with anti-brazzein antibodies. Secretion of brazzein into the medium has not led to significant yield increase. Surprisingly, optimizing the codon usage for Lactococcus lactis led to a decrease in the yield of brazzein.
authors.affiliation: Department of Biochemistry and Molecular Biology, Jozef Stefan Institute, Jamova 39, SI-1000, Ljubljana, Slovenia. ales.berlec@ijs.si
authors.forename: Ales
authors.initials: A
authors.lastname: Berlec
authors.forename: Zala
authors.initials: Z
authors.lastname: Jevnikar
authors.forename: Andreja Canzek
authors.initials: AC
authors.lastname: Majhenic
authors.forename: Irena
authors.initials: I
authors.lastname: Rogelj
authors.forename: Borut
authors.initials: B
authors.lastname: Strukelj
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D015870:Gene Expression; D013294:Lactococcus lactis / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000235:genetics; D013549:Sweetening Agents; D013649:Taste
chemical_list: D010940:Plant Proteins; D011994:Recombinant Proteins; D013549:Sweetening Agents; C090521:brazzein protein, Pentadiplandra brazzeana