title: Molecular characterization, homology modeling and docking studies of the R2787H missense variation in BRCA2 gene: Association with breast cancer.
abstract: The significance of many BRCA unclassified variants (UVs) has not been evaluated. Classification of these variations as neutral or pathogenic presents a significant challenge and has important implications for breast and ovarian cancer genetic counseling. Here we report a combined molecular and computational approach to classify BRCA UVs missense variations. By using the LOH (Loss of heterozygosity) analysis at the BRCA1/BRCA2 loci, five bioinformatics approaches namely fathmm, PhD-SNP, SNAP, MutationTaster and Human Splicing Finder and the association with the clinico-pathological characteristics related to BRCA tumors, we were able to classify the R2787H (in BRCA2 gene) variant as pathogenic. Then, to investigate the functional role of the R2787H variation in altering BRCA2 structure, the homology model of this variant was constructed using the Rattus norvegicus BRCA2 (PDB ID: 1IYJ) as a template. The predicted model was then assessed for stereochemical quality and side chain environment. Furthermore, docking and binding free energy simulations were performed to investigate the ssDNA-BRCA2 complex interaction. Binding energy value calculation proves that this substitution affects the complex stability. Moreover, this alteration was not found in one hundred healthy controls. These findings suggest that R2787H variant could have potential functional impact. Our approach might be useful for evaluation of BRCA unclassified variants. However additional functional analyzes may provide appropriate assessment to classify such variants.
authors.affiliation: Laboratoire Génétique Humaine, Faculté de Médecine de Tunis, Université Tunis El manar, Tunisia. Electronic address: Aouatef.riahi@gmail.com.
authors.forename: Aouatef
authors.initials: A
authors.lastname: Riahi
authors.affiliation: Higher Institute of Biotechnology of Beja, Tunisia. Electronic address: messaoudiabdelmonemster@gmail.com.
authors.forename: Abdelmonem
authors.initials: A
authors.lastname: Messaoudi
authors.affiliation: Department of Hereditary and Congenital Disorders, Charles Nicolle Hospital, Tunisia. Electronic address: rmrad@yahoo.com.
authors.forename: Ridha
authors.initials: R
authors.lastname: Mrad
authors.affiliation: Department of Immunohistocytology, Salah Azaiz Institute, Tunis, Tunisia. Electronic address: asma.fourati@rns.tn.
authors.forename: Asma
authors.initials: A
authors.lastname: Fourati
authors.affiliation: Department of Hereditary and Congenital Disorders, Charles Nicolle Hospital, Tunisia. Electronic address: habiba.chabouni@rns.tn.
authors.forename: Habiba
authors.initials: H
authors.lastname: Chabouni-Bouhamed
authors.affiliation: Laboratoire Génétique Humaine, Faculté de Médecine de Tunis, Université Tunis El manar, Tunisia. Electronic address: maher.kharrat@fmt.rnu.tn.
authors.forename: Maher
authors.initials: M
authors.lastname: Kharrat
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D024682:BRCA2 Protein / Q000737:chemistry / Q000235:genetics; D001943:Breast Neoplasms / Q000235:genetics*; D016022:Case-Control Studies; D005260:Female; D024522:Genes, BRCA2; D056426:Genetic Loci; D020022:Genetic Predisposition to Disease; D018095:Germ-Line Mutation / Q000235:genetics; D006801:Humans; D019656:Loss of Heterozygosity / Q000235:genetics; D018895:Microsatellite Repeats / Q000235:genetics; D062105:Molecular Docking Simulation; D020125:Mutation, Missense / Q000235:genetics*; D051381:Rats; D015203:Reproducibility of Results; D016415:Sequence Alignment; D040681:Structural Homology, Protein
chemical_list: D024682:BRCA2 Protein
keywords: BRCA2 gene; Breast cancer; Homology modeling; Unclassified variant