The New Functional Hybrid Chaperone Protein ADGroEL-SacSm.

The creation of new proteins by combining natural domains is a commonly used technique in protein engineering. In this work, we have tested the possibilities and limitations of using circular homo-oligomeric Sm-like proteins as a basis for attaching other domains. Attachment to such a stable base should bring target domains together and keep them in the correct mutual orientation.

The Denaturant- and Mutation-Induced Disassembly of Hexameric Hfq Y55W Mutant.

Although oligomeric proteins are predominant in cells, their folding is poorly studied at present. This work is focused on the denaturant- and mutation-induced disassembly of the hexameric mutant Y55W of the Qβ host factor (Hfq) from mesophilic (). Using intrinsic tryptophan fluorescence, dynamic light scattering (DLS), and high-performance liquid chromatography (HPLC), we show that the dissociation of Hfq Y55W occurs either under the effect of GuHCl or during the pre-denaturing transition, when the protein concentration is decreased, with both events proceeding through the accumulation of stable intermediate states.

Structure and RNA-Binding Properties of Lsm Protein from Halobacterium salinarum.

The structure and the RNA-binding properties of the Lsm protein from Halobacterium salinarum have been determined. A distinctive feature of this protein is the presence of a short L4 loop connecting the β3 and β4 strands. Since bacterial Lsm proteins (also called Hfq proteins) have a short L4 loop and form hexamers, whereas archaeal Lsm proteins (SmAP) have a long L4 loop and form heptamers, it has been suggested that the length of the L4 loop may affect the quaternary structure of Lsm proteins.

Diversity of LSM Family Proteins: Similarities and Differences.

Members of the Lsm protein family are found in all three domains of life: bacteria, archaea, and eukarya. They are involved in numerous processes associated with RNA processing and gene expression regulation. A common structural feature of all Lsm family proteins is the presence of the Sm fold consisting of a five-stranded β-sheet and an α-helix at the N-terminus.