Effect of site-directed replacement mutations to channel-lining arginine in flagellin on protein transport and motility in Salmonella typhimurium

Abstract

The bacterial flagellum is a highly conserved, autoassembling structure which enables motility. The flagellum consists of three parts: a basal body inside the cell, a hook structure, and an external flagellar filament, which is typically several times longer than the cell body. The flagellar filament is a narrow tube-like structure composed of a single protein, flagellin, which is diffused down the channel at the center of the filament as it is assembled. Four amino acids constitute the flagellar channel. The terminal amino acid which lines this channel is arginine, which is polar and carries a positive charge. This study endeavored to ascertain whether the positive charge, polarity, or size of arginine is necessary for protein transport and successful auto-assembly of the flagellar filament.