A disulfide linked model of the complement protein C8γ complexed with C8α indel peptide
In a recent study C8γ (complement protein) with Cys40Ala substitution and a C8α derived peptide with Cys164Ala substitution were co-crystallized and their binding mode was revealed. Computer modeling and molecular dynamics simulations were performed in order to check the hypothesis that the residues Ala164 of C8α and Ala40 of C8γ occupied the right position if cysteine residues were in their place for disulfide bonding. Substitution of these two alanine residues with cysteine along with disulfide bond creation via molecular modeling and subsequent molecular dynamics simulation of the complex corroborated the hypothesis, which was also confirmed from recent crystallographic data. Average RMSD between backbone atoms of the indel peptide during the MD trajectory in comparison with the corresponding sequence of crystal structure of the C8α/γ complex was found only 0.085 nm.
KeywordsC8α/γ complex Complement protein Computer simulation Membrane attack complex Molecular dynamics
NAMD parallel execution was performed at the Research Center of Scientific Simulations (RCSS) of University of Ioannina. The open source community is gratefully acknowledged for making publicly available all the computational tools (Linux, NAMD, GNU tools, etc) needed for this research.
- 2.Steckel EW, York RG, Monahan JB, Sodetz JM (1980) The eighth component of human complement. Purification and physicochemical characterization of its unusual subunit structure. J Biol Chem 255:11997–12005Google Scholar
- 6.Lovelace LL, Chiswell B, Slade DJ, Sodetz JM, Lebioda L (2008) Crystal structure of complement protein C8gamma in complex with a peptide containing the C8gamma binding site on C8alpha: implications for C8gamma ligand binding. Mol Immunol 45:750–756. doi: 10.1016/j.molimm.2007.06.359 CrossRefGoogle Scholar
- 10.van Gunsteren WF, Dolenc J, Mark AE (2008) Molecular simulation as an aid to experimentalists. Curr Opin Struct Biol 18:149–153Google Scholar
- 23.Delano W (2002). The PYMOL Molecular Graphics System (Delano Scientific, San Carlos, CA)Google Scholar