Expression, purification, and characterization of diacylated Lipo-YcjN from Escherichia coli.

YcjN is a putative substrate binding protein expressed from a cluster of genes involved in carbohydrate import and metabolism in Escherichia coli. Here, we determine the crystal structure of YcjN to a resolution of 1.95 Å, revealing that its three-dimensional structure is similar to substrate binding proteins in subcluster D-I, which includes the well-characterized maltose binding protein.

Expression, purification, and characterization of diacylated Lipo-YcjN from .

YcjN is a putative substrate-binding protein expressed from a cluster of genes involved in carbohydrate import and metabolism in . Here, we determine the crystal structure of YcjN to a resolution of 1.95 Å, revealing that its three-dimensional structure is similar to substrate binding proteins in subcluster D-I, which includes the well-characterized maltose binding protein (MBP).

Resolving the enthalpy of protein stabilization by macromolecular crowding.

Proteins in the cellular milieu reside in environments crowded by macromolecules and other solutes. Although crowding can significantly impact the protein folded state stability, most experiments are conducted in dilute buffered solutions. To resolve the effect of crowding on protein stability, we use F nuclear magnetic resonance spectroscopy to follow the reversible, two-state unfolding thermodynamics of the N-terminal Src homology 3 domain of the Drosophila signal transduction protein drk in the presence of polyethylene glycols (PEGs) of various molecular weights and concentrations.

Macromolecular Crowding Is More than Hard-Core Repulsions.

Cells are crowded, but proteins are almost always studied in dilute aqueous buffer. We review the experimental evidence that crowding affects the equilibrium thermodynamics of protein stability and protein association and discuss the theories employed to explain these observations. In doing so, we highlight differences between synthetic polymers and biologically relevant crowders.

A Difference between and In-Cell Protein Dimer Formation.

The high concentration of macromolecules in cells affects the stability of proteins and protein complexes via hard repulsions and chemical interactions, yet few studies have focused on chemical interactions. We characterized the domain-swapped dimer of the B1 domain of protein G in buffer and cells by using heteronuclear, multidimensional nuclear magnetic resonance spectroscopy. In buffer, the monomer is a partially folded molten globule, but that species is not observed in cells.