Purification and characterization of bovine steroid 21-hydroxylase (P450c21) efficiently expressed in Escherichia coli

• Published in: Biochemical and biophysical research communications Vol. 344; no. 1; pp. 400 - 405
• Main Authors: Arase, Miharu, Waterman, Michael R., Kagawa, Norio
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 26.05.2006
• Subjects: 17-alpha-Hydroxyprogesterone - chemistry; Animals; Cattle - metabolism; Congenital adrenal hyperplasia; CYP21; Cytochrome P-450 Enzyme System - genetics; Escherichia coli; Escherichia coli - enzymology; Escherichia coli - genetics; Escherichia coli - metabolism; Escherichia coli expression; Genetic Engineering - methods; Molecular chaperone; Progesterone - chemistry; Recombinant Proteins - biosynthesis; Recombinant Proteins - chemistry; Recombinant Proteins - isolation & purification; Solubility; Steroid 21-Hydroxylase - biosynthesis; Steroid 21-Hydroxylase - chemistry; Steroid 21-Hydroxylase - isolation & purification; Steroid hormone; CYP21; Congenital adrenal hyperplasia; Steroid hormone; Escherichia coli expression; Molecular chaperone
• ISSN: 0006-291X; 1090-2104
• DOI: 10.1016/j.bbrc.2006.03.067

Steroid 21-hydroxylase, P450c21, is responsible for the conversion of progesterone and 17α-hydroxyprogesterone to their 21-hydroxylated derivatives. P450c21 has been poorly investigated because of difficulty in obtaining sufficient quantities of purified protein. To solve the problem, we have attempted to express the bovine P450c21 in Escherichia coli as a stable form. The N-terminal membrane anchor and basic regions of P450c21 were replaced by the basic region of CYP2C3. The engineered P450c21 was expressed at a level higher than 1.2 μmol/L culture (>60 mg/L) when coexpressed with molecular chaperones GroES/GroEL. Utilizing three steps of column chromatography, the protein was highly purified to the specific content 16.6 nmol/mg (91.2% purity). The purified protein is a monomer in the presence of 1% sodium cholate as determined by gel filtration analysis, suggesting that this membrane anchor-truncated form of P450c21 is more soluble than the native form. The purified enzyme showed typical substrate-binding difference spectra and 21-hydroxylase activities for both progesterone and 17α-hydroxyprogesterone. Truncation of the membrane anchor increases solubility of P450c21 facilitating expression of this protein in E. coli yielding sufficient quantities for both biochemical and biophysical studies.