THREADING A NARROW NEEDLE

Abstract

A HIGH-RESOLUTION CRYSTAL structure obtained by Jorge E. Galan, a microbiologist at Yale School of Medicine, and former postdoc C. Erec Stebbins, now at Rockefeller University, sheds some light on the type III secretion system used by many pathogenic bacteria to inject effector proteins into host eukaryotic cells. structure could help in identifying or designing compounds to interfere with the secretion system. This type III delivery system consists of a needlelike appendage on the surface of the bacterium. bacterial proteins have to travel through this needle to reach the cell. However, the opening of the needle is only about A—too small for a folded protein to fit through. The $64,000 question has always been, 'How do the proteins travel through these particular structures?' Galân says. Each protein is associated with a chaperone protein inside the bacterial cell. chaperones are vital to the operation of the secretion system, but what hasn't been ...