title: [Expression of functionally active hyman cytochrome P-450c21 (CYPXXIA2) in Escherichia coli and single-stage purification of it using metal-affinity chromatography].
abstract: Active human cytochrome P-450c21 was expressed in Escherichia coli and purified to homogeneity. To increase expression, cDNA encoding for the N-terminal fragment of cytochrome P-450c21 was modified. Four histidine codons were added to cDNA encoding for the C-terminus of the protein; thus, recombinant protein could have been rapidly and effectively purified by metal-affinity chromatography. Modified human cytochrome P-450c21 was expressed (40-50 nmoles/l of culture according to spectrophotometry) which was able to bind to bacterial membrane. Modifications of N- and C-terminal regions of cytochrome P-450c21 did not change Km and Vmax for hydroxylation of progesterone and 17 alpha-hydroxyprogesterone in reconstituted system. Recombinant cytochrome P-450c21 was purified to apparent homogeneity from Escherichia coli membrane extract by metal-affinity chromatography. Purified cytochrome P-450c21 migrates as a single 54 kD band on polyacrylamide gel and exhibits type I spectral changes during interaction with progesterone and 17 alpha-hydroxyprogesterone. Activity of purified cytochrome P-450c21 was reconstituted with mouse liver microsomal NADPH-cytochrome P-450-reductase and NADPH-regenerating system. Purified enzyme had Km 12.2 and 3.21 microM and Vmax 192.9 and 198 nmoles/min/nmole of P-450c21 for 17 alpha-hydroxyprogesterone and progesterone, respectively. According to titration spectra, dissociation constants for progesterone and 17 alpha-hydroxy-progesterone were 14.7 and 31.1 microM, respectively.
authors.forename: V M
authors.initials: VM
authors.lastname: Guzov
authors.forename: I N
authors.initials: IN
authors.lastname: Zel'ko
authors.forename: M V
authors.initials: MV
authors.lastname: Chudaev
authors.forename: Iu A
authors.initials: IuA
authors.lastname: Guzova
authors.forename: Ch
authors.initials: Ch
authors.lastname: Bon-Chu
authors.forename: S A
authors.initials: SA
authors.lastname: Usanov
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002846:Chromatography, Affinity / Q000379:methods*; D003001:Cloning, Molecular; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D018076:DNA, Complementary; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000235:genetics; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D010957:Plasmids; D013255:Steroid 21-Hydroxylase; D013379:Substrate Specificity
chemical_list: D018076:DNA, Complementary; D003577:Cytochrome P-450 Enzyme System; D013255:Steroid 21-Hydroxylase