Molecular modeling, mutational analysis and conformational switching in IL27: An in silico structural insight towards AIDS research
GENE
Authors: Banerjee, Arundhati; Ray, Sujay
Abstract
The advancement in proteomics and bioinformatics provokes to discern the molecular-level probe for HIV inhibitor; human interleukin-27 (IL27). Documentation documents that tyrosine residues in 1127 play a pivotal role for interacting with HIV, causing apoptosis of the HIV+ cells. Primarily, 3D structure of human wild-type (WT) 1127 was built through manifold molecular modeling techniques after the satisfaction of stereo-chemical properties. Its essential tyrosine residues were identified. Two mutant models for 1127 were prepared following the similar protocol by first substituting the tyrosine residues with glycine (MT_G) and then with alanine (MT_A) in the WT protein. Molecular dynamics (MD) simulation was performed to obtain a stable conformation. Conformational alterations in WT, MT_G and MT_A (before and after MD simulation) disclosed that MT_A was the steadiest one with the best secondary structure conformation supported by statistical significances. Though huge RMSD variations were observed on superimposing the MT structures on WT individually, the MTs were examined to share similar SCOP/CATH fold with TM-score = 0.8, indicating that they retained their functionality even after mutation. Electrostatic surface potential again unveiled MT_A to be the most stable one. MT_A was thereby revealed to be the potent peptide inhibitor for HIV. This probe presents a pathway to investigate and compare the bio-molecular interaction of WT IL27 and MT_A IL27 (strongest model) with HIV in the future. This is the first report regarding the structural biology of 1127 accompanied by alteration at its genetic level and delving into the unknown residue-level and functional biochemistry for bringing about an annihilation towards AIDS. (C) 2015 Elsevier B.V. All rights reserved.
Prediction of type 1 diabetes using a genetic risk model in the Diabetes Autoimmunity Study in the Young
PEDIATRIC DIABETES
Authors: Frohnert, Brigitte I.; Laimighofer, Michael; Krumsiek, Jan; Theis, Fabian J.; Winkler, Christiane; Norris, Jill M.; Ziegler, Anette-Gabriele; Rewers, Marian J.; Steck, Andrea K.
Abstract
Background: Genetic predisposition for type 1 diabetes (T1D) is largely determined by human leukocyte antigen (HLA) genes; however, over 50 other genetic regions confer susceptibility. We evaluated a previously reported 10-factor weighted model derived from the Type 1 Diabetes Genetics Consortium to predict the development of diabetes in the Diabetes Autoimmunity Study in the Young (DAISY) prospective cohort. Performance of the model, derived from individuals with first-degree relatives (FDR) with T1D, was evaluated in DAISY general population (GP) participants as well as FDR subjects. Methods: The 10-factor weighted risk model (HLA, PTPN22, INS, IL2RA, ERBB3, ORMDL3, BACH2, IL27, GLIS3, RNLS), 3-factor model (HLA, PTPN22, INS), and HLA alone were compared for the prediction of diabetes in children with complete SNP data (n = 1941). Results: Stratification by risk score significantly predicted progression to diabetes by Kaplan-Meier analysis (GP: P=.00006; FDR: P=.0022). The 10-factor model performed better in discriminating diabetes outcome than HLA alone (GP, P=.03; FDR, P=.01). In GP, the restricted 3-factor model was superior to HLA (P=.03), but not different from the 10-factor model (P=.22). In contrast, for FDR the 3-factor model did not show improvement over HLA (P=.12) and performed worse than the 10-factor model (P=.02) Conclusions: We have shown a 10-factor risk model predicts development of diabetes in both GP and FDR children. While this model was superior to a minimal model in FDR, it did not confer improvement in GP. Differences in model performance in FDR vs GP children may lead to important insights into screening strategies specific to these groups.