Analysis of Amino Acid Sidechain Chi1, Chi2 Conformational Properties Using Quantum Mechanical and Experimental Crystallographic Survey Data

Xiao Zhu, Pedro Lopes, Jihyun Shim, Alexander D. MacKerell
2011 Biophysical Journal  
Sortase A cleaves a C-terminal sorting signal of the surface proteins at a conserved LPXTG motif with the help of a calcium ion, leading to adhesion to the cell wall peptideglycan. The solution structures with and without a peptide (LPAT) reveal that a disordered loop undergoes a disorder-to-order transition upon peptide binding. Comprehensive conformational sampling of the disordered loop has been performed to elucidate how flexible the disordered loop in the peptide free form is and how the
more » ... ptide and calcium binding affect the flexibility. The free energy landscape thus calculated clarifies the role of the calcium ion in the enzyme activity.
doi:10.1016/j.bpj.2010.12.1010 fatcat:nk22iya5u5bnpit4ismnbjbj3m