Correlation Between Protein Primary Sequence Structure and Soluble Expression Level of dAbs in Escherichia coli

Lots of antibody drug have been successfully expressed in the prokaryotic system. Lacking knowledge on the process mechanism of recombinant protein expression has forced researchers to use "trial and error" to improve soluble production, which is time and labor consuming with low success rate. Adding different amino acids to the C-terminal of a dAb often results in significant variation of soluble expression levels. The amino acid sequence of dAbs highly concords with their soluble expression levels, with a consistency being 70%. Through analyzing the soluble expression and sequence data of 65 dAbs using clustering and linear modeling, we show that certain amino acids panel could significantly affect the soluble expression of dAbs, with the specific amino acids composition in these panels being(S, R, N, D, Q), (G, R, C, N, S) and(R, S, G), respectively, in the supernatant, pellet and total amount. In addition, polar was found a vital factor affecting the soluble production of dAb. These results may be helpful in orthomutation.