Mechanism of deep-sea fish α-actin pressure tolerance investigated by molecular dynamics simulations.
The pressure tolerance of monomeric α-actin proteins from the deep-sea fish Coryphaenoides armatus and C. yaquinae was compared to that of non-deep-sea fish C. acrolepis, carp, and rabbit/human/chicken actins using molecular dynamics simulations at 0.1 and 60 MPa. The amino acid sequences of actins are highly conserved across a variety of species. The actins from C. armatus and C. yaquinae have the specific substitutions Q137K/V54A and Q137K/L67P, respectively, relative to C. acrolepis, and are pressure tolerant to depths of at least 6000 m. At high pressure, we observed significant changes in the salt bridge patterns in deep-sea fish actins, and these changes are expected to stabilize ATP binding and subdomain arrangement. Salt bridges between ATP and K137, formed in deep-sea fish actins, are expected to stabilize ATP binding even at high pressure. At high pressure, deep-sea fish actins also formed a greater total number of salt bridges than non-deep-sea fish actins owing to the formation of inter-helix/strand and inter-subdomain salt bridges. Free energy analysis suggests that deep-sea fish actins are stabilized to a greater degree by the conformational energy decrease associated with pressure effect.
Department of Computational Biology, Graduate School of Frontier Sciences, The University of Tokyo, Tokyo, Japan.
Nobuhiko
N
Wakai
Institute of Molecular and Cellular Biosciences, The University of Tokyo, Tokyo, Japan.
Kazuhiro
K
Takemura
Research Center for Fisheries Oceanography and Marine Ecosystem, National Research Institute of Fisheries Sciences, Fisheries Research Agency, Kanagawa, Japan.
Takami
T
Morita
Institute of Molecular and Cellular Biosciences, The University of Tokyo, Tokyo, Japan.
Akio
A
Kitao
D000199:Actins / Q000378:metabolism*; D000818:Animals; D002645:Chickens; D048388:Gadiformes / Q000378:metabolism*; D006801:Humans; D056004:Molecular Dynamics Simulation; D011312:Pressure; D011817:Rabbits; D013045:Species Specificity
D000199:Actins