Singh Pratishtha, Ganjiwale Anjali, Howlett Allyn C, Cowsik Sudha M
School of Life Sciences, Jawaharlal Nehru University, New Delhi 110067, India.
Department of Life Sciences, Bangalore University, Bangalore 560056, India.
J Mol Graph Model. 2017 Oct;77:311-321. doi: 10.1016/j.jmgm.2017.09.006. Epub 2017 Sep 6.
Cannabinoid Receptor Interacting Protein isoform 1b (CRIP1b) is known to interact with the CB receptor. Alternative splicing of the CNRIP1 gene produces CRIP1a and CRIP1b with a difference in the third exon only. Exons 1 and 2 encode for a functional domain in both proteins. CRIP1a is involved in regulating CB receptor internalization, but the function of CRIP1b is not very well characterized. Since there are significant identities in functional domains of these proteins, CRIP1b is a potential target for drug discovery. We report here predicted structure of CRIP1b followed by its interaction analysis with CB receptor by in-silico methods A number of complementary computational techniques, including, homology modeling, ab-initio and protein threading, were applied to generate three-dimensional molecular models for CRIP1b. The computed model of CRIP1b was refined, followed by docking with C terminus of CB receptor to generate a model for the CRIP1b- CB receptor interaction. The structure of CRIP1b obtained by homology modelling using RHO_GDI-2 as template is a sandwich fold structure having beta sheets connected by loops, similar to predicted CRIP1a structure. The best scoring refined model of CRIP1b in complex with the CB receptor C terminus peptide showed favourable polar interactions. The overall binding pocket of CRIP1b was found to be overlapping to that of CRIP1a. The Arg82 and Cys126 of CRIP1b are involved in the majority of hydrogen bond interactions with the CB receptor and are possible key residues required for interactions between the CB receptor and CRIP1b.
大麻素受体相互作用蛋白亚型1b(CRIP1b)已知与CB受体相互作用。CNRIP1基因的可变剪接产生CRIP1a和CRIP1b,仅在第三个外显子上存在差异。外显子1和2编码这两种蛋白质的一个功能域。CRIP1a参与调节CB受体的内化,但CRIP1b的功能尚未得到很好的表征。由于这些蛋白质的功能域存在显著的同源性,CRIP1b是药物发现的潜在靶点。我们在此报告CRIP1b的预测结构,随后通过计算机模拟方法对其与CB受体的相互作用进行分析。应用了多种互补的计算技术,包括同源建模、从头计算和蛋白质穿线法,来生成CRIP1b的三维分子模型。对计算得到的CRIP1b模型进行了优化,然后与CB受体的C末端进行对接,以生成CRIP1b - CB受体相互作用的模型。以RHO_GDI - 2为模板通过同源建模获得的CRIP1b结构是一种三明治折叠结构,具有由环连接的β折叠片,类似于预测的CRIP1a结构。与CB受体C末端肽结合的CRIP1b最佳评分优化模型显示出有利的极性相互作用。发现CRIP1b的整体结合口袋与CRIP1a的重叠。CRIP1b的Arg82和Cys126参与了与CB受体的大部分氢键相互作用,并且可能是CB受体与CRIP1b相互作用所需的关键残基。