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Team:Goettingen/project overview/project drylab
From 2014.igem.org
Project
Dry lab
Homology modelling
We modeled the 3D structure of our peptide-containing scaffolds (domain B1 of protein G from Staphylococcus aureus) by homology modelling. We used Modeller library to accomplish that; since the peptide is about 20-25 amino acid residues long, it can be modeled as a loop inside the B1 domain scaffold for which there are already a number of 3D structures available at the Protein Data Bank.
Figure: Depicting the procedure for Homology modeling: All peptides were cloned inside a scaffold (B1 domain of protein G from Staphylococcus aureus. The peptides were short enough to be modeled as an internal loop by loop refinement; however, these structures should only be considered as a working model, since we don't have direct crystallographic data.
Results summary
We obtained working structural models for our peptides inside their scaffolds. The following table is a summary of them. Please note that these models are not definitive, since they were obtained by homology modeling and loop refinement. Their main purpose is to give us an idea if the calculated energy profile matches our assumption that the peptide is being exposed to the exterior of the scaffold.
| Peptide | PNG* | PDB | Peptide location | QMEAN score | Overall DOPE score | Energy profile |
|---|---|---|---|---|---|---|
| Prey 3 |  |
Download | K17-E42 | 0.512 | -7053.966797 | Download |
| Prey 4.1 |  |
Download | K17-E44 | 0.468 | -7246.956055 | Download |
| Prey 5 |  |
Download | K17-E44 | 0.495 | -7501.071777 | Download |
| Prey 13 |  |
Download | K17-E42 | 0.535 | -7729.056152 | Download |
| Prey 15 |  |
Download | K17-E42 | 0.447 | -7671.660156 | Download |
*The peptide is shown in red and the scaffold in blue.
This is peptide IGP4 that shows interaction with ssr1 protein from Candida glabrata
References
- 1. N. Eswar, M. A. Marti-Renom, B. Webb, M. S. Madhusudhan, D. Eramian, M. Shen, U. Pieper, A. Sali. Comparative Protein Structure Modeling With MODELLER. Current Protocols in Bioinformatics, John Wiley & Sons, Inc., Supplement 15, 5.6.1-5.6.30, 2006.
- 2. M.A. Marti-Renom, A. Stuart, A. Fiser, R. Sánchez, F. Melo, A. Sali. Comparative protein structure modeling of genes and genomes. Annu. Rev. Biophys. Biomol. Struct. 29, 291-325, 2000.
- 3. A. Sali & T.L. Blundell. Comparative protein modelling by satisfaction of spatial restraints. J. Mol. Biol. 234, 779-815, 1993.
- 4. A. Fiser, R.K. Do, & A. Sali. Modeling of loops in protein structures, Protein Science 9. 1753-1773, 2000.
