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Archaea S‐layer nanotube from a “black smoker” in complex with cyclo‐octasulfur (S8) rings |
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| Authors: | Matthew McDougall Olga Francisco Candice Harder‐Viddal Roy Roshko Markus Meier Jörg Stetefeld |
| Affiliation: | 1. Department of Chemistry, University of Manitoba, 144 Dysart Rd, Winnipeg, Manitoba, Canada;2. Center for Oil and Gas Research and Development (COGRAD), Winnipeg, Manitoba, Canada;3. Department of Chemistry and Physics, Canadian Mennonite University, 500 Shaftesbury Blvd, Winnipeg, Manitoba, Canada;4. Department of Physics and Astronomy, University of Manitoba, 30A Sifton Rd, Winnipeg, Manitoba, Canada;5. Department of Biochemistry and Medical Genetics, University of Manitoba, Winnipeg, Manitoba, Canada;6. Department of Human Anatomy and Cell Science, University of Manitoba, Winnipeg, Manitoba, Canada |
| Abstract: | Elemental sulfur exists primarily as an  ring 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‐octasulfur  . 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 sulfur  from 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. |
| Keywords: | structural biology MD simulations archaea S‐layer proteins S8 crown in protein cavities coiled‐coil protein dynamic light scattering right‐handed coiled coil |
