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Archaea S‐layer nanotube from a “black smoker” in complex with cyclo‐octasulfur ( S 8 ) rings
Author(s) -
McDougall Matthew,
Francisco Olga,
HarderViddal Candice,
Roshko Roy,
Meier Markus,
Stetefeld Jörg
Publication year - 2017
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.25385
Subject(s) - archaea , sulfur , ring (chemistry) , molecular dynamics , chemical physics , chemistry , nanotube , carbon nanotube , thermodynamic integration , nanotechnology , computational chemistry , materials science , organic chemistry , biochemistry , gene
Elemental sulfur exists primarily as anS 8 0ring and serves as terminal electron acceptor for a variety of sulfur‐fermenting bacteria. Hyperthermophilic archaea from black smoker vents are an exciting research tool to advance our knowledge of sulfur respiration under extreme conditions. Here, we use a hybrid method approach to demonstrate that the proteinaceous cavities of the S‐layer nanotube of the hyperthermophilic archaeon Staphylothermus marinus act as a storage reservoir for cyclo‐octasulfurS 8. Fully atomistic molecular dynamics (MD) simulations were performed and the method of multiconfigurational thermodynamic integration was employed to compute the absolute free energy for transferring a ring of elemental sulfurS 8from an aqueous bath into the largest hydrophobic cavity of a fragment of archaeal tetrabrachion. Comparisons with earlier MD studies of the free energy of hydration as a function of water occupancy in the same cavity of archaeal tetrabrachion show that the sulfur ring is energetically favored over water.