scholarly journals Design structure of fusion protein of bovine DNA exotransferase and E. coli SSB protein

Author(s):  
A. B. Sachanka ◽  
Ya. U. Dzichenka ◽  
A. V. Yantsevich ◽  
S. A. Usanov

The analysis of the trajectories of molecular dynamics simulation and spatial structures of homologous models of fusion protein with various linkers was performed to understand the effect of the additional DNA-binding domain of the E. coli SSB protein attached to the truncated and native bovine DNA exotransferase on its stability and activity. It is found that the C-terminus of the enzyme is the preferred end for attachment of the E. coli protein, while the stability of the truncated fusion enzyme is higher than the native one. According to molecular dynamics data, introducing linkers between two proteins for the native (GGGGSGGGSGGGGS, GGGSGGGS, and TCT) and truncated (GGSGGGSGG, GGGGGG, GTGSGT, and 5xGGGGS) forms of the enzyme not only improves its stability, but also increases the mutual mobility of DNA-affinity domains.

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7329 ◽  
Author(s):  
Changyu Shan ◽  
Hongwei Li ◽  
Yuping Zhang ◽  
Yuyan Li ◽  
Yingchun Chen ◽  
...  

Epididymal protease inhibitor (EPPIN) that is located on the sperm surface and specific to the male reproductive system is a non-hormonal contraceptive target, since the binding of EPPIN with the seminal plasma protein semenogelin-1 (SEMG1) causes a loss of sperm function. Here, we investigated the binding interactions between EPPIN and SEMG1 by homology modeling, docking and molecular dynamics simulation. Since no crystal structure was reported for EPPIN, its 3D structure was constructed by homology modeling and refined by dynamics simulation, illustrating the C-terminus domain of EPPIN could bind with its N-terminus domain through the residues 30–32 and 113–116. The binding interaction of SEMG110-8 peptide and EPPIN was investigated by Z-DOCK and dynamics simulation. After evaluating the models according to the calculated binding free energies, we demonstrated that C-terminus domain of EPPIN was important for the binding of SEMG1 via residues Tyr107, Gly112, Asn116, Gln118 and Asn122, while residue Arg32 in N-terminus domain also had contribution for their binding interaction. Additionally, the binding pocket of EPPIN was defined according to these key residues and verified by molecular docking with reported inhibitor EP055, suggesting that the pocket formed by Arg32, Asn114, Asn116, Phe117 and Asn122 could be important for the design of new ligands. This study might be helpful for the understanding of biological function of EPPIN and would encourage the discovery of non-hormonal contraceptive leads/drugs in the future.


2019 ◽  
Vol 19 (2) ◽  
pp. 461
Author(s):  
Herlina Rasyid ◽  
Bambang Purwono ◽  
Thomas S Hofer ◽  
Harno Dwi Pranowo

Lung cancer was a second common cancer case due to the high cigarette smoking activity both in men and women. One of protein receptor which plays an important role in the growth of the tumor is Epidermal Growth Factor Receptor (EGFR). EGFR protein is the most frequent protein mutation in cancer and promising target to inhibit the cancer growth. In this work, the stability of the hydrogen bond as the main interaction in the inhibition mechanism of cancer will be evaluated using molecular dynamics simulation. There were two compounds (A1 and A2) as new potential inhibitors that were complexed against the EGFR protein. The dynamic properties of each complexed were compared with respect to erlotinib against EGFR. The result revealed that both compounds had an interaction in the main catalytic area of protein receptor which is at methionine residue. Inhibitor A1 showed additional interactions during simulation time but the interactions tend to be weak. Inhibitor A2 displayed a more stable interaction. Following dynamics simulation, binding free energy calculation was performed by two scoring techniques MM/GB(PB)SA method and gave a good correlation with the stability of the complex. Furthermore, potential inhibitor A2 had a lower binding free energy as a direct consequence of the stability of hydrogen bond interaction.


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