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Structure and stability of a model three‐helix‐bundle protein on tailored surfaces
Author(s) -
Knotts Thomas A.,
Rathore Nitin,
de Pablo Juan J.
Publication year - 2005
Publication title -
proteins: structure, function, and bioinformatics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.699
H-Index - 191
eISSN - 1097-0134
pISSN - 0887-3585
DOI - 10.1002/prot.20581
Subject(s) - cooperativity , helix bundle , chemistry , crystallography , helix (gastropod) , thermal stability , enthalpy , molecular dynamics , thermodynamics , work (physics) , peptide , molecule , bundle , chemical physics , protein structure , materials science , computational chemistry , physics , biochemistry , biology , ecology , organic chemistry , snail , composite material
The interaction of protein molecules with surfaces is important in numerous applications. Theoretical work on protein adsorption has been limited. In particular, it is difficult to obtain quantitative predictions about the structure and stability of proteins on surfaces. In this study, density‐of‐states‐based simulations were performed on a Gō‐like model of a three‐helix‐bundle fragment from protein A (PDB ID: 1bdd). Both mechanical and thermal stability were investigated on neutral and attractive surfaces and compared to that in the absence of a surface. It was found that attaching the peptide to any type of surface decreases its melting temperature by as much as 9 K, depending upon orientation. Calorimetric cooperativity, as measured by van't Hoff to calorimetric enthalpy ratios, similarly decreased. It was also found that the mechanical strength of the peptide attached to surfaces is degraded to varying extents, depending upon the surface type and protein orientation. A comparison of mechanical and thermal stability showed that the two are not synonymous, but occur through different pathways, and that system configurations that are more thermally stable are not always so mechanically. Proteins 2005. © 2005 Wiley‐Liss, Inc.