37 research outputs found
Characterisation of a new family of carboxyl esterases with an OsmC domain
Proteins in the serine esterase family are widely distributed in bacterial phyla and display
activity against a range of biologically produced and chemically synthesized esters. A serine
esterase from the psychrophilic bacterium Pseudoalteromonas arctica with a C-terminal
OsmC-like domain was recently characterized; here we report on the identification and characterization
of further putative esterases with OsmC-like domains constituting a new esterase
family that is found in a variety of bacterial species from different environmental niches.
All of these proteins contained the Ser-Asp-His motif common to serine esterases and a
highly conserved pentapeptide nucleophilic elbow motif. We produced these proteins heterologously
in Escherichia coli and demonstrated their activity against a range of esterase
substrates. Two of the esterases characterized have activity of over two orders of magnitude
higher than other members of the family, and are active over a wide temperature
range. We determined the crystal structure of the esterase domain of the protein from Rhodothermus
marinus and show that it conforms to the classical α/β hydrolase fold with an
extended ‘lid’ region, which occludes the active site of the protein in the crystal. The expansion
of characterized members of the esterase family and demonstration of activity over a
wide-range of temperatures could be of use in biotechnological applications such as the
pharmaceutical, detergent, bioremediation and dairy industries
Structural and functional characterisation of multi‐copper oxidase CueO from lignin‐degrading bacterium Ochrobactrum
Characterization of amylolytic and pullulytic enzymes from thermophilic archaea and from a newFervidobacterium species
Discovery of piperonal-converting oxidase involved in the metabolism of a botanical aromatic aldehyde
Reassembly of an Integral Oligomeric Membrane Protein OmpF Porin in n-octyl β-d-Glucopyranoside–Lipids Mixtures
Freely suspended perforated polymer nanomembranes for protein separations
Abstract Selective removal of nanometer-sized compounds such as proteins from fluids is an often challenging task in many scientific and industrial areas. Addressing such tasks with highly efficient and selective membranes is desirable since commonly used chromatographic approaches are expensive and difficult to scale up. Nanomembranes, molecularly thin separation layers, have been predicted and shown to possess outstanding properties but in spite ultra-fast diffusion times and high-resolution separation, to date they generally lack either of two crucial characteristics: compatibility with biological fluids and low-cost production. Here we report the fast and easy fabrication of highly crosslinked polymer membranes based on a thermoset resin (poly[(o-cresyl glycidyl ether)-co-formaldehyde (PCGF) cured with branched polyethyleneimine (PEI)) with nanoscale perforations of 25 nm diameter. During spin casting, microphase separation of a polylactide-co-glycolide induces the formation of nanometer sized domains that serve as templates for perforations which penetrate the 80 nm thick membranes. Ultrathin perforated nanomembranes can be freely suspended on the cm scale, exhibit high mechanical strength, low surface energies and a sharp permeability cutoff at a hydrodynamic diameter of 10 nm suitable for protein separations