Lavarti Rupa, Ganugapati Jayasree, Ratcha Shirisa, Rao Lakshmana Ss, SivaSai Krovvidi Sr
Department of Biotechnology, Sreenidhi Institute of Science & Technology, Ghatkesar, Hyderabad - 501301.
Bioinformation. 2016 Aug 15;12(5):293-299. doi: 10.6026/97320630012293. eCollection 2016.
Peptides of Rv0679c a membrane protein of the cell envelope (16.6 KDa) of Mycobacterium tuberculosis (M. tb), inhibited entry of live bacilli into epithelial (A549) and macrophage (U937) cell lines in vitro, suggesting a possible role in invasion. Receptors associated with Rv0679c antigen entry into cell lines were not characterized. We are reporting that Rv0679c peptides could bind to Toll like receptors (TLRs), the principal class of pathogen recognition receptors on host cells (PRR) by docking studies. Peptide structures were predicted using PEP FOLD and docking of truncated peptides with TLR's was performed using Cluspro 2.0. Docked complexes were analyzed using Swiss-PDB Viewer. Nine peptides of Rv0679c protein assessed were able to bind to TLR2-1 and TLR 4-MD2; however the binding energy was better with TLR 4-MD2. Peptide 30985 (-866.4 kcal/mol) has better binding energy with TLR2-1, in contrast peptide 30982 showed a better binding energy to TLR 4-MD2 dimer with a score of -1291.7 kcal/mol. Interactive residue analysis revealed that GLU 173 and SER 454 of TLR 1; ARG 447 and ARG 486 of TLR2; ARG 264 of TLR 4 and SER 120, LYS 122 and GLU 92 of MD2 region are predominant residues interacting with peptides of Rv0679c protein. Our study suggests that predominant residues and receptors of TLR2 and TLR4 are important for Rv0679c protein binding, which could further lead to invasion of M. tb into the host cell.
结核分枝杆菌（M. tb）细胞包膜的一种膜蛋白Rv0679c（16.6千道尔顿）的肽段，在体外可抑制活杆菌进入上皮细胞系（A549）和巨噬细胞系（U937），提示其在侵袭过程中可能发挥作用。与Rv0679c抗原进入细胞系相关的受体尚未明确。我们通过对接研究报告称，Rv0679c肽段可与Toll样受体（TLRs）结合，TLRs是宿主细胞上主要的病原体识别受体类别（PRR）。使用PEP FOLD预测肽段结构，并使用Cluspro 2.0进行截短肽段与TLR的对接。使用Swiss-PDB Viewer分析对接复合物。评估的Rv0679c蛋白的九个肽段能够与TLR2-1和TLR 4-MD2结合；然而，与TLR 4-MD2的结合能更好。肽段30985（-866.4千卡/摩尔）与TLR2-1具有更好的结合能，相比之下，肽段30982与TLR 4-MD2二聚体的结合能更好，得分为-1291.7千卡/摩尔。相互作用残基分析显示，TLR 1的GLU 173和SER 454；TLR2的ARG 447和ARG 486；TLR 4的ARG 264以及MD2区域的SER 120、LYS 122和GLU 92是与Rv0679c蛋白肽段相互作用的主要残基。我们的研究表明，TLR2和TLR4的主要残基和受体对于Rv0679c蛋白结合很重要，这可能进一步导致结核分枝杆菌侵入宿主细胞。
