title: Molecular model of human CYP21 based on mammalian CYP2C5: structural features correlate with clinical severity of mutations causing congenital adrenal hyperplasia.
abstract: Enhanced understanding of structure-function relationships of human 21-hydroxylase, CYP21, is required to better understand the molecular causes of congenital adrenal hyperplasia. To this end, a structural model of human CYP21 was calculated based on the crystal structure of rabbit CYP2C5. All but two known allelic variants of missense type, a total of 60 disease-causing mutations and six normal variants, were analyzed using this model. A structural explanation for the corresponding phenotype was found for all but two mutants for which available clinical data are also discrepant with in vitro enzyme activity. Calculations of protein stability of modeled mutants were found to correlate inversely with the corresponding clinical severity. Putative structurally important residues were identified to be involved in heme and substrate binding, redox partner interaction, and enzyme catalysis using docking calculations and analysis of structurally determined homologous cytochrome P450s (CYPs). Functional and structural consequences of seven novel mutations, V139E, C147R, R233G, T295N, L308F, R366C, and M473I, detected in Scandinavian patients with suspected congenital adrenal hyperplasia of different severity, were predicted using molecular modeling. Structural features deduced from the models are in good correlation with clinical severity of CYP21 mutants, which shows the applicability of a modeling approach in assessment of new CYP21 mutations.
authors.affiliation: Department of Molecular Medicine and Surgery, Center for Molecular Medicine (CMM) L8:02, Karolinska Institutet/Karolinska University Hospital, S-17176 Stockholm, Sweden. tiina.robins@ki.se
authors.forename: Tiina
authors.initials: T
authors.lastname: Robins
authors.forename: Jonas
authors.initials: J
authors.lastname: Carlsson
authors.forename: Maria
authors.initials: M
authors.lastname: Sunnerhagen
authors.forename: Anna
authors.initials: A
authors.lastname: Wedell
authors.forename: Bengt
authors.initials: B
authors.lastname: Persson
mesh_terms: D000312:Adrenal Hyperplasia, Congenital / Q000209:etiology* / Q000235:genetics*; D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D003577:Cytochrome P-450 Enzyme System / Q000737:chemistry*; D000072467:Cytochrome P450 Family 2; D004795:Enzyme Stability; D014644:Genetic Variation; D006418:Heme / Q000737:chemistry; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D008958:Models, Molecular; D008969:Molecular Sequence Data; D050505:Mutant Proteins / Q000737:chemistry; D009154:Mutation; D010084:Oxidation-Reduction; D011485:Protein Binding; D025941:Protein Interaction Mapping; D017433:Protein Structure, Secondary; D011817:Rabbits; D012720:Severity of Illness Index; D013045:Species Specificity; D013255:Steroid 21-Hydroxylase / Q000737:chemistry* / Q000235:genetics*; D013256:Steroids / Q000378:metabolism; D013329:Structure-Activity Relationship
chemical_list: D050505:Mutant Proteins; D013256:Steroids; D006418:Heme; D003577:Cytochrome P-450 Enzyme System; C065407:CYP2C5 protein, Oryctolagus cuniculus; D000072467:Cytochrome P450 Family 2; D013255:Steroid 21-Hydroxylase