EFFECT OF BACITRACIN ON FLAGELLAR ASSEMBLY AND PRESUMED GLYCOSYLATIONOF THE FLAGELLINS OF METHANOCOCCUS-DELTAE

Methanococeus deltae is an irregularly-shaped coccoid methanogen which possesses peritrichously arranged flagella. The flagella are composed of 2 flagellins of M(r) = 27000 and 32000 and possess a carbohydrate component as determined by thymol-sulfuric acid staining of SDS-PAGE. Cell growth was sensitive to bacitracin at levels near 10 mug/ml. Grow th in the presence of 5 mug/ml bacitracin resulted in the appearance o f presumably hypoglycosylated flagellins as detected by Western immuno blotting. Continual passage of cells from 5 mug/ml bacitracin through 10, 25, and 50 mug/ml bacitracin resulted in cells capable of growth a t 100 mug/ml bacitracin. Western immunoblot analysis revealed that cel ls grown in the highest concentration of bacitracin no longer possesse d native' flagellins but only the hypoglycosylated forms. Electron mic roscopy corroborated the absence of normal flagella. These studies sug gest that a bacitracin-sensitive dolichol-diphosphate carrier is respo nsible for attachment of at least a large proportion of the carbohydra te content of the flagellins, and that a minimum amount of glycosylati on is essential for normal flagellum assembly.