Environmental factors influence the Haloferax volcanii S-layer protein structure.

Autor: Rodrigues-Oliveira T; Department of Cell Biology, Institute of Biological Sciences, University of Brasília, Brasília, Brazil., Souza AA; Department of Cell Biology, Institute of Biological Sciences, University of Brasília, Brasília, Brazil., Kruger R; Department of Cell Biology, Institute of Biological Sciences, University of Brasília, Brasília, Brazil., Schuster B; Department of NanoBiotechnology, Institute for Synthetic Bioarchitectures, University of Natural Resources and Life Sciences, Vienna, Austria., Maria de Freitas S; Department of Cell Biology, Institute of Biological Sciences, University of Brasília, Brasília, Brazil., Kyaw CM; Department of Cell Biology, Institute of Biological Sciences, University of Brasília, Brasília, Brazil.
Jazyk: angličtina
Zdroj: PloS one [PLoS One] 2019 May 10; Vol. 14 (5), pp. e0216863. Date of Electronic Publication: 2019 May 10 (Print Publication: 2019).
DOI: 10.1371/journal.pone.0216863
Abstrakt: S-layers commonly cover archaeal cell envelopes and are composed of proteins that self-assemble into a paracrystalline surface structure. Despite their detection in almost all archaea, there are few reports investigating the structural properties of these proteins, with no reports exploring this topic for halophilic S-layers. The objective of the present study was to investigate the secondary and tertiary organization of the Haloferax volcanii S-layer protein. Such investigations were performed using circular dichroism, fluorescence spectroscopy, dynamic light scattering and transmission electron microscopy. The protein secondary structure is centered on β-sheets and is affected by environmental pH, with higher disorder in more alkaline conditions. The pH can also affect the protein's tertiary structure, with higher tryptophan side-chain exposure to the medium under the same conditions. The concentrations of Na, Mg and Ca ions in the environment also affect the protein structures, with small changes in α-helix and β-sheet content, as well as changes in tryptophan side chain exposure. These changes in turn influence the protein's functional properties, with cell envelope preparations revealing striking differences when in different salt conditions. Thermal denaturation assays revealed that the protein is stable. It has been reported that the S-layer protein N-glycosylation process is affected by external factors and the present study indicates for the first time changes in the protein structure.
Competing Interests: The authors have declared that no competing interests exist.
Databáze: MEDLINE
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