As a single-cell organism, Vibrio cholerae depends on resources in its immediate environment to sustain itself. Blanca Barquera, assistant professor of biology at Rensselaer and principal investigator for the project, studies an enzyme that resides in the membrane that encapsulates V. cholerae. This enzyme, known as NQR, pumps sodium ions out of the bacteria to generate a difference in concentrations between outside and inside. This gradient acts like a battery that powers essential cell functions, such as the movement of the bacterium’s tail, the flagellum.
Most cells, including human cells, use gradients of protons for this energy conservation function, but enzymes that work with sodium ions are ideal for experimental study, according to Barquera. Sodium is easier to trace and its concentration can be changed without affecting pH, which is a complication with protons. "It’s a very good system to understand this very basic mechanism charging this battery to create energy," she said.
In order to learn how the enzyme works, researchers are trying to get an idea of its three-dimensional structure. "The enzyme is like two machines together ?imagine the turbine and generator of a hydroelectric dam. One is the source of energy; the other uses this energy to pump ions out of the cell," Barquera said. How the two machines are connected is one key question.
In the first paper, published in the Journal of Bacteriology, Barquera tackled the question of how the structure of the enzyme is organized with respe
Source:Rensselaer Polytechnic Institute