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Study of the stability and unfolding mechanism of BBA1 by molecular dynamics simulations at different temperatures
Author(s) -
Wang Lu,
Duan Yong,
Shortle Rebecca,
Imperiali Barbara,
Kollman Peter A.
Publication year - 1999
Publication title -
protein science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.353
H-Index - 175
eISSN - 1469-896X
pISSN - 0961-8368
DOI - 10.1110/ps.8.6.1292
Subject(s) - molecular dynamics , mechanism (biology) , stability (learning theory) , dynamics (music) , chemical physics , chemistry , statistical physics , physics , thermodynamics , computational chemistry , computer science , quantum mechanics , machine learning , acoustics
BBA1 is a designed protein that has only 23 residues. It is the smallest protein without disulfide bridges that has a well‐defined tertiary structure in solution. We have performed unfolding molecular dynamics simulations on BBA1 and some of its mutants at 300, 330, 360, and 400 K to study their kinetic stability as well as the unfolding mechanism of BBA1. It was shown that the unfolding simulations can provide insights into the forces that stabilize the protein. Packing, hydrophobic interactions, and a salt bridge between Asp12 and Lys16 were found to be important to the protein' stability. The unfolding of BBA1 goes through two major steps: (1) disruption of the hydrophobic core and (2) unfolding of the helix. The β‐hairpin remains stable in the unfolding because of the high stability of the type II' turn connecting the two β‐strands.