title: Functional and Structural Analyses of CYP1B1 Variants Linked to Congenital and Adult-Onset Glaucoma to Investigate the Molecular Basis of These Diseases.
abstract: Glaucoma, the leading cause of irreversible blindness, appears in various forms. Mutations in CYP1B1 result in primary congenital glaucoma (PCG) by an autosomal recessive mode of inheritance while it acts as a modifier locus for primary open angle glaucoma (POAG). We investigated the molecular basis of the variable phenotypes resulting from the defects in CYP1B1 by using subclones of 23 CYP1B1 mutants reported in glaucoma patients, in a cell based system by measuring the dual activity of the enzyme to metabolize both retinol and 17β-estradiol. Most variants linked to POAG showed low steroid metabolism while null or very high retinol metabolism was observed in variants identified in PCG. We examined the translational turnover rates of mutant proteins after the addition of cycloheximide and observed that the levels of enzyme activity mostly corroborated the translational turnover rate. We performed extensive normal mode analysis and molecular-dynamics-simulations-based structural analyses and observed significant variation of fluctuation in certain segmental parts of the mutant proteins, especially at the B-C and F-G loops, which were previously shown to affect the dynamic behavior and ligand entry/exit properties of the cytochrome P450 family of proteins. Our molecular study corroborates the structural analysis, and suggests that the pathologic state of the carrier of CYP1B1 mutations is determined by the allelic state of the gene. To our knowledge, this is the first attempt to dissect biological activities of CYP1B1 for correlation with congenital and adult onset glaucomas.
authors.affiliation: Molecular & Human Genetics Division, CSIR-Indian Institute of Chemical Biology, 4, Raja S.C. Mullick Road, Jadavpur, Kolkata-700032, India.
authors.forename: Antara
authors.initials: A
authors.lastname: Banerjee
authors.affiliation: Molecular & Human Genetics Division, CSIR-Indian Institute of Chemical Biology, 4, Raja S.C. Mullick Road, Jadavpur, Kolkata-700032, India.
authors.forename: Subhadip
authors.initials: S
authors.lastname: Chakraborty
authors.affiliation: Structural Biology and Bio-Informatics Division, CSIR-Indian Institute of Chemical Biology, 4, Raja S.C. Mullick Road, Jadavpur, Kolkata-700032, India.
authors.forename: Abhijit
authors.initials: A
authors.lastname: Chakraborty
authors.affiliation: Structural Biology and Bio-Informatics Division, CSIR-Indian Institute of Chemical Biology, 4, Raja S.C. Mullick Road, Jadavpur, Kolkata-700032, India.
authors.forename: Saikat
authors.initials: S
authors.lastname: Chakrabarti
authors.affiliation: Molecular & Human Genetics Division, CSIR-Indian Institute of Chemical Biology, 4, Raja S.C. Mullick Road, Jadavpur, Kolkata-700032, India.|Academy of Scientific & Innovative Research (AcSIR), Central Road Research Institute, Delhi-Mathura Road, New Delhi-110025, India.
authors.forename: Kunal
authors.initials: K
authors.lastname: Ray
mesh_terms: D000328:Adult; D000595:Amino Acid Sequence; D001120:Arginine / Q000737:chemistry; D002460:Cell Line; D017124:Conserved Sequence; D065633:Cytochrome P-450 CYP1B1 / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D004958:Estradiol / Q000378:metabolism; D056726:Genetic Association Studies; D014644:Genetic Variation; D005901:Glaucoma / Q000151:congenital / Q000201:enzymology* / Q000235:genetics*; D057809:HEK293 Cells; D006801:Humans; D007231:Infant, Newborn; D056004:Molecular Dynamics Simulation; D050505:Mutant Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D009154:Mutation; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D014801:Vitamin A / Q000378:metabolism
chemical_list: D050505:Mutant Proteins; D011994:Recombinant Proteins; D014801:Vitamin A; D004958:Estradiol; D001120:Arginine; C585496:CYP1B1 protein, human; D065633:Cytochrome P-450 CYP1B1