2003/12/16 by Marek Cieplak, Cieplak, Marek, Trinh Xuan Hoang +3
Biochemistry, Genetics and Molecular Biology · Physics and Astronomy · #Biomolecules (q-bio.BM) #FOS: Biological sciences #FOS: Physical sciences #Soft Condensed Matter (cond-mat.soft) #cond-mat.soft #q-bio.BM
paper · pdf · doi:10.48550/arxiv.q-bio/0312023
38 pages, 17 figures, to appear in Proteins
arxiv created 2003/12/16 · arxiv updated 2009/12/01
The effect of temperature on mechanical unfolding of proteins is studied using a Go-like model with a realistic contact map and Lennard-Jones contact interactions. The behavior of the I27 domain of titin and its serial repeats is contrasted to that of simple secondary structures. In all cases thermal fluctuations accelerate the unraveling process, decreasing the unfolding force nearly linearly at low temperatures. However differences in bonding geometry lead to different sensitivity to temperature and different changes in the unfolding pattern. Due to its special native state geometry titin is much more thermally and elastically stable than the secondary structures. At low temperatures serial repeats of titin show a parallel unfolding of all domains to an intermediate state, followed by serial unfolding of the domains. At high temperatures all domains unfold simultaneously and the unfolding distance decreases monotonically with the contact order, that is the sequence distance between the amino acids that form the native contact.