Crystal structures of organotungsten complexes formed by sequential insertion of elemental sulfur into tungsten-carbon bonds

1987 ◽  
Vol 6 (1) ◽  
pp. 7-9 ◽  
Author(s):  
Stephen V. Evans ◽  
Peter. Legzdins ◽  
Steven J. Rettig ◽  
Luis. Sanchez ◽  
James. Trotter
Keyword(s):  
Crystal Structures ◽  
Elemental Sulfur ◽  
Carbon Bonds

scholarly journals Organic Stabilization of Extracellular Elemental Sulfur in a Sulfurovum-Rich Biofilm: A New Role for Extracellular Polymeric Substances?

2021 ◽  
Vol 12 ◽  
Author(s):  
Brandi Cron ◽  
Jennifer L. Macalady ◽  
Julie Cosmidis
Keyword(s):  
Crystal Structures ◽  
Extracellular Polymeric Substances ◽  
Elemental Sulfur ◽  
Dense Matrix ◽  
Cave System ◽  
Carboxylic Groups ◽  
Sulfur Oxidizing ◽  
New Evidence ◽  
Sulfur Oxidizing Bacteria

This work shines light on the role of extracellular polymeric substance (EPS) in the formation and preservation of elemental sulfur biominerals produced by sulfur-oxidizing bacteria. We characterized elemental sulfur particles produced within a Sulfurovum-rich biofilm in the Frasassi Cave System (Italy). The particles adopt spherical and bipyramidal morphologies, and display both stable (α-S8) and metastable (β-S8) crystal structures. Elemental sulfur is embedded within a dense matrix of EPS, and the particles are surrounded by organic envelopes rich in amide and carboxylic groups. Organic encapsulation and the presence of metastable crystal structures are consistent with elemental sulfur organomineralization, i.e., the formation and stabilization of elemental sulfur in the presence of organics, a mechanism that has previously been observed in laboratory studies. This research provides new evidence for the important role of microbial EPS in mineral formation in the environment. We hypothesize that the extracellular organics are used by sulfur-oxidizing bacteria for the stabilization of elemental sulfur minerals outside of the cell wall as a store of chemical energy. The stabilization of energy sources (in the form of a solid electron acceptor) in biofilms is a potential new role for microbial EPS that requires further investigation.

scholarly journals Catalytic Intermediate Crystal Structures of Cysteine Desulfurase from the Archaeon Thermococcus onnurineus NA1

Archaea ◽  
2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Thien-Hoang Ho ◽  
Kim-Hung Huynh ◽  
Diem Quynh Nguyen ◽  
Hyunjae Park ◽  
Kyoungho Jung ◽  
...  
Keyword(s):  
Crystal Structures ◽  
Elemental Sulfur ◽  
Catalytic Mechanism ◽  
Cysteine Desulfurase ◽  
Thermococcus Onnurineus Na1 ◽  
Iron Sulfur Cluster ◽  
Terminal Electron Acceptor ◽  
Iron Sulfur ◽  
Angle Rotation ◽  
Sulfur Containing

Thermococcus onnurineus NA1 is an anaerobic archaeon usually found in a deep-sea hydrothermal vent area, which can use elemental sulfur (S0) as a terminal electron acceptor for energy. Sulfur, essential to many biomolecules such as sulfur-containing amino acids and cofactors including iron-sulfur cluster, is usually mobilized from cysteine by the pyridoxal 5′-phosphate- (PLP-) dependent enzyme of cysteine desulfurase (CDS). We determined the crystal structures of CDS from Thermococcus onnurineus NA1 (ToCDS), which include native internal aldimine (NAT), gem-diamine (GD) with alanine, internal aldimine structure with existing alanine (IAA), and internal aldimine with persulfide-bound Cys356 (PSF) structures. The catalytic intermediate structures showed the dihedral angle rotation of Schiff-base linkage relative to the PLP pyridine ring. The ToCDS structures were compared with bacterial CDS structures, which will help us to understand the role and catalytic mechanism of ToCDS in the archaeon Thermococcus onnurineus NA1.

Insertion of Elemental Sulfur and SO2into the Metal−Hydride and Metal−Carbon Bonds of Platinum Compounds

1999 ◽  
Vol 18 (2) ◽  
pp. 227-234 ◽  
Author(s):  
Michael S. Morton ◽  
Rene J. Lachicotte ◽  
David A. Vicic ◽  
William D. Jones
Keyword(s):  
Metal Hydride ◽  
Elemental Sulfur ◽  
Platinum Compounds ◽  
Carbon Bonds
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