Display of Oligo-α-1,6-Glycosidase from Exiguobacterium sibiricum on the Surface of Escherichia coli Cells.

Cell-surface display using anchor motifs of outer membrane proteins allows exposure of target peptides and proteins on the surface of microbial cells. Previously, we obtained and characterized highly catalytically active recombinant oligo-α-1,6-glycosidase from the psychrotrophic bacterium Exiguobacterium sibiricum (EsOgl). It was also shown that the autotransporter AT877 from Psychrobacter cryohalolentis and its deletion variants efficiently displayed type III fibronectin (Fn3) domain 10 on the surface of Escherichia coli cells.

Deletion Variants of Autotransporter from Psychrobacter cryohalolentis Increase Efficiency of FN3 Exposure on the Surface of Escherichia coli Cells.

The autotransporter AT877 from Psychrobacter cryohalolentis belongs to the family of outer membrane proteins containing N-terminal passenger and C-terminal translocator domains that form the basis for the design of display systems on the surface of bacterial cells. It was shown in our previous study that the passenger domain of AT877 can be replaced by the cold-active esterase EstPc or the tenth domain of fibronectin type III (Fn3). In order to increase efficiency of the Fn3 surface display in Escherichia coli cells, four deletion variants of the Fn877 hybrid autotransporter were obtained.

Engineering of Thermal Stability in a Cold-Active Oligo-1,6-Glucosidase from with Unusual Amino Acid Content.

A gene coding for a novel putative amylase, oligo-1,6-glucosidase from a psychrotrophic bacterium from Siberian permafrost soil was cloned and expressed in . The amino acid sequence of the predicted protein EsOgl and its 3D model displayed several features characteristic for the cold-active enzymes while possessing an unusually high number of proline residues in the loops-a typical feature of thermophilic enzymes. The activity of the purified recombinant protein was tested with -nitrophenyl α-D-glucopyranoside as a substrate.

Increased Synthesis of a Magnesium Transporter MgtA During Recombinant Autotransporter Expression in Escherichia coli.

Overproduction of the membrane proteins in Escherichia coli cells is a common approach to obtain sufficient material for their functional and structural studies. However, the efficiency of this process can be limited by toxic effects which decrease the viability of the host and lead to low yield of the product. During the expression of the esterase autotransporter AT877 from Psychrobacter cryohalolentis K5, we observed significant growth inhibition of the C41(DE3) cells in comparison with the same cells producing other recombinant proteins.

Chimeric antibodies against tick-borne encephalitis virus.

Two chimeric antibodies (ch) 13D6 and 10C2 against the glycoprotein E of tick-borne encephalitis virus (TBEV) were constructed by fusing variable regions of murine monoclonal antibodies (Mabs) 13D6 and 10C2 to human constant regions. Monovalent analogues of these antibodies in format of single-chain antibodies (scFv or sc) were developed, as well. The ch13D6, ch10C2, sc13D6 and sc10C2 exhibited binding characteristics similar to parental Mabs.

NMR structural and dynamical investigation of the isolated voltage-sensing domain of the potassium channel KvAP: implications for voltage gating.

The structure and dynamics of the isolated voltage-sensing domain (VSD) of the archaeal potassium channel KvAP was studied by high-resolution NMR. The almost complete backbone resonance assignment and partial side-chain assignment of the (2)H,(13)C,(15)N-labeled VSD were obtained for the protein domain solubilized in DPC/LDAO (2:1) mixed micelles. Secondary and tertiary structures of the VSD were characterized using secondary chemical shifts and NOE contacts.

Lipid-protein nanodiscs as reference medium in detergent screening for high-resolution NMR studies of integral membrane proteins.

The choice of a suitable detergent-based membrane mimetic is of crucial importance for high-resolution NMR studies of membrane proteins. The present report describes a new approach of detergent screening. It is based on the comparison of 2D (1)H,(15)N-correlation spectra of a protein in a membrane-bilayer "reference" medium and in "trial" detergent-based environments.

Methods for preparation of recombinant cytokine proteins V. mutant analogues of human interferon-gamma with higher stability and activity.

Mutant analogues of recombinant human immune interferon (IFN-gamma) with higher stability and biological activity were prepared. Depending on the analogue, protein structure modification might involve introduction of an intramonomer disulfide bond (through replacements of Glu7Cys and Ser69Cys), C-terminal shortening by 10 amino acid residues, as well as Gln133Leu substitution in truncated variant. Isolation, purification, and renaturation of the IFN-gamma analogues expressed in Escherichia coli as inclusion bodies were performed according to the scheme developed earlier for wild-type protein.