Ketol-acid reductoisomerase (EC 1.1.1.86) catalyses the second reaction in the biosynthesis of branched-chain amino acids. The reaction involves an Mg2+ -dependent alkyl migration followed by an NADPH-dependent reduction of the 2-keto group. Here, the crystallization of the Escherichia coli enzyme is reported. A form with a C-terminal hexahistidine tag could be crystallized under 18 different c...

Interleukin (IL)-33 is the latest member of IL-1 cytokine family. In this study, the cloning, expression, purification, and polyclonal antibody preparation of mouse IL-33 were described. The coding region of IL-33 mature protein was cloned into the prokaryotic expression vector pET-44. The recombinant protein, IL-33 containing a hexahistidine tag in the C-terminal, was expressed in Escherichia ...

Polyhistidine affinity tags are routinely employed as a convenient means of purifying recombinantly expressed proteins. A tacit assumption is commonly made that His tags have little influence on protein structure and function. Attachment of a His tag to the N-terminus of the robust globular protein myoglobin leads to only minor changes to the electrostatic environment of the heme pocket, as evi...

Emergence of fungal strains showing resistance to triazole drugs can make treatment of fungal disease problematic. Triazole resistance can arise due to single mutations in the drug target lanosterol 14α-demethylase (Erg11p/CYP51). We have determined how commonly occurring single site mutations in pathogenic fungi affect triazole binding using Saccharomyces cerevisiae Erg11p (ScErg11p) as a targ...

Dendritic cells (DCs) are potent stimulators of immunity, and DCs pulsed with tumor antigen ex vivo have applications in tumor immunotherapy. However, DCs are a small population of cells, and their isolation and pulsing with antigen can be impractical. Here we show that a crude preparation of plasma membrane vesicles (PMV) from the highly metastatic murine melanoma (B16-OVA) and a surrogate tum...

The sensor kinase CitA and the response regulator CitB of Klebsiella pneumoniae form the paradigm of a subfamily of bacterial two-component regulatory systems that are capable of sensing tri- or dicarboxylates in the environment and then induce transporters for the uptake of these compounds. We recently showed that the separated periplasmic domain of CitA, termed CitAP (encompasses residues 45-...

In the field of biotechnology, fusing recombinant proteins to highly soluble partners is a common practice for overcoming aggregation in Escherichia coli. E. coli maltose-binding protein (MBP) has been recognized as one of the most effective solubilizing agents, having frequently been observed to improve the yield, enhance the solubility, and promote the proper folding of its fusion partners. T...

A generic protocol that utilizes a dual hexahistidine-maltose-binding protein (His6-MBP) affinity tag has been developed for the production of recombinant proteins in Escherichia coli. The MBP moiety improves the yield and enhances the solubility of the passenger protein while the His-tag facilitates its purification. The fusion protein (His6-MBP-passenger) is purified by immobilized metal affi...

Single-stranded DNA (ssDNA)-binding proteins play an essential role in DNA replication and repair. They use oligonucleotide/oligosaccharide-binding (OB)-folds, a five-stranded β-sheet coiled into a closed barrel, to bind to ssDNA thereby protecting and stabilizing the DNA. In eukaryotes the ssDNA-binding protein (SSB) is known as replication protein A (RPA) and consists of three distinct subuni...