Bacterial Proteins on the Move

Cell surface materials passed via direct contact can restart the engines of stalled myxococci.

Charles Choi(
Jun 30, 2005

Scientists have identified the first known instance of bacterial transfer of cell surface proteins through direct contact, they report in Science this week. Such protein sharing in Myxococcus xanthus helps mobile bacteria get immobile mutants moving, Dale Kaiser at Stanford University in California and colleagues found.

"The genome for Myxococcus has recently been finished, and they actually have a very large number of outer membrane lipoproteins," Kaiser told The Scientist. "An as-yet unknown number of these are transferable."

M. xanthus is a rod-shaped, soil-dwelling bacterium that uses a pair of mechanisms to move. At the trailing end of the organism the A motility engine extrudes slime that pushes the bacteria forward, while at the leading end the S engine projects type IV pili, which pull the bacteria ahead.

M. xanthus with mutant Tgl, an outer membrane lipoprotein involved in the S engine, have slime extrusion but lack pili....