Effects of N-Terminal and C-Terminal Polyhistidine Tag on the Stability and Function of the Thermophilic P450 CYP119

Abstract EN

Biocatalysts are sought-after in synthesis of pharmaceuticals and agrochemicals due to their high regioselectivity and enantioselectivity.

Among biocatalysts, heme-containing cytochrome P450 (P450) oxygenases are an attractive target since they catalyze oxidation of “unactivated” carbon-hydrogen bonds with high efficiency.

CYP119 is an acidothermophilic P450 from Sulfolobus acidocaldarius, which has the potential to be widely used as a biocatalyst since it shows activity at high temperatures and low pH.

Polyhistidine tags (His-tags) are widely used to simplify purification of proteins.

However, His-tags can cause changes to protein structure and function.

Here, we demonstrate the effects of His-tags on CYP119.

To this end, the His-tags were cloned at the N-terminus or C-terminus of the CYP119, and His-tagged proteins were expressed and isolated.

The thermostability and peroxidase activity of His-tagged CYP119s were tested and compared to wild type CYP119.

Results indicated that while addition of His-tags increased the yield and simplified isolation of CYP119, they also influenced the electronic structure of active site and the activity of the protein.

We show that N-terminal His-tagged CYP119 has desirable properties and potential to be used in industrial applications, but mechanistic studies using this protein need careful interpretation since the His-tag affects electronic properties of the active site heme iron.