Fragment based G-QSAR and molecular dynamics based mechanistic simulations into hydroxamic-based HDAC inhibitors against spinocerebellar ataxia.
Expansion of polyglutamine (CAG) triplets within the coding gene ataxin 2 results in transcriptional repression, forming the molecular basis of the neurodegenerative disorder named spinocerebellar ataxia type-2 (SCA2). HDAC inhibitors (HDACi) have been elements of great interest in polyglutamine disorders such as Huntington's and Ataxia's. In this study, we have selected hydroxamic acid derivatives as HDACi and performed fragment-based G-QSAR, molecular docking studies and molecular dynamics simulations for elucidating the dynamic mode of action of HDACi with His-Asp catalytic dyad of HDAC4. The model was statistically validated to establish its predictive robustness. The model was statistically significant with r(2) value of .6297, cross-validated co-relation coefficient q(2) value of .5905 and pred_r(2) (predicted square co-relation coefficient) value of .85. An F-test value of 56.11 confirms absolute robustness of the model. Two combinatorial libraries comprising of 3180 compounds were created with hydroxamate moiety as the template and their pIC50 activities were predicted based on the G-QSAR model. The combinatorial library created was screened on the basis of predicted activity (pIC50), with two resultant top scoring compounds, HIC and DHC. The interaction of the compounds with His-Asp dyad in terms of H-bond interactions with His802, Asp840, Pro942, and Gly975 residues of HDAC4 was evaluated by docking and 20 ns long molecular dynamics simulations. This study provides valuable leads for structural substitutions required for hydroxamate moiety to exhibit enhanced inhibitory activity against HDAC4. The reported compounds demonstrated good binding and thus can be considered as potent therapeutic leads against ataxia.
a Department of Biotechnology , TERI University , 10 Institutional Area, Vasant Kunj, New Delhi 110070 , India.
Siddharth
S
Sinha
b Indian Agricultural Research Institute , PUSA Road, New Delhi 110012 , India.
Chetna
C
Tyagi
c Department of Bioscience and Biotechnology , Banasthali University , Tonk , Rajasthan 304022 , India.
Sukriti
S
Goyal
c Department of Bioscience and Biotechnology , Banasthali University , Tonk , Rajasthan 304022 , India.
Salma
S
Jamal
a Department of Biotechnology , TERI University , 10 Institutional Area, Vasant Kunj, New Delhi 110070 , India.
Pallavi
P
Somvanshi
d School of Biotechnology , Jawaharlal Nehru University , New Delhi 110067 , India.
Abhinav
A
Grover
D001665:Binding Sites; D015195:Drug Design; D056572:Histone Deacetylase Inhibitors / Q000737:chemistry* / Q000494:pharmacology; D006860:Hydrogen Bonding; D006877:Hydroxamic Acids / Q000737:chemistry* / Q000494:pharmacology; D008968:Molecular Conformation; D062105:Molecular Docking Simulation; D056004:Molecular Dynamics Simulation; D011485:Protein Binding; D021281:Quantitative Structure-Activity Relationship; D054852:Small Molecule Libraries; D020754:Spinocerebellar Ataxias / Q000188:drug therapy
D056572:Histone Deacetylase Inhibitors; D006877:Hydroxamic Acids; D054852:Small Molecule Libraries
G-QSAR; HDAC inhibitors; ataxin 2; spinocerebellar ataxia type-2