Energetics of SecA Dimerization

Analysis of SecA Dimerization in Solution

The Sec pathway mediates translocation of protein across the inner membrane of bacteria. SecA is a motor protein that drives translocation of preprotein through the SecYEG channel. SecA reversibly dimerizes under physiological conditions, but different dimer interfaces have been observed in SecA crystal structures. Here, we have used biophysical approaches to address the nature of the SecA dime...

Energetics of outer membrane phospholipase A (OMPLA) dimerization.

Outer membrane phospholipase A (OMPLA) is a widely conserved transmembrane enzyme found in Gram-negative bacteria, and it is implicated in the virulence of a number of pathogenic organisms. The regulation of the protein's phospholipase activity is not well understood despite the existence of a number of high resolution structures. Previous biochemical studies have demonstrated that dimerization...

Energetics of cooperative binding of oligonucleotides with discrete dimerization domains to DNA by triple helix formation.

Cooperativity in oligonucleotide-directed sequence-specific recognition of DNA by triple helix formation can be enhanced by the addition of discrete dimerization domains. The equilibrium association constants for cooperative binding of oligonucleotides that dimerize by Watson-Crick hydrogen bonds and occupy adjacent sites on double helical DNA by triple helix formation have been measured by qua...

Reexamination of the role of the amino terminus of SecA in promoting its dimerization and functional state.

The SecA nanomotor promotes protein translocation in eubacteria by binding both protein cargo and the protein-conducting channel and by undergoing ATP-driven conformation cycles that drive this process. There are conflicting reports about whether SecA functions as a monomer or dimer during this dynamic process. Here we reexamined the roles of the amino and carboxyl termini of SecA in promoting ...

Discovery of a shortened version of SecA (SecA) that conceivably functions as a protein-conducting channel