Many proteins of higher organisms are oligomers consisting of more than one polypeptide chain, and recombinant production of these complexes in an active form often requires simultaneous co-expression of the individual polypeptides. LEXSY allows up to four different antibiotic selection markers that can be used for expression of up to four different proteins simultaneously facilitating production of functional oligomers.
LEXSY was used to express human laminin-332 (α3β3γ2), a large heterotrimeric glycoprotein and essential component of epithelial basal lamina that promotes cell adhesion and migration (Phan et al. 2009).
Model of heterotrimeric laminin-332 (left) and Western blot of purified 420 kDa laminin heterotrimer separated under non-reducing conditions. Lanes 1 molecular size marker (kDa), 2 laminin from 293-F cells (2 forms), 3 laminin from LEXSY (one defined form) after Phan et al. (2009).
Alternatively, avoiding limitation by availability of selection markers in vivo, oligomeric proteins can be obtained using In Vitro LEXSY by co-expession of the respective polypeptides in the same extract.