Effects of a gerF (lgt) mutation on the germination of spores of Bacillus subtilis

One of the proteins of the membrane-bound receptors that recognize individual nutrients that trigger germination of spores of Bacillus subtilis contains the recognition sequence for diacylglycerol addition to a cysteine residue near the protein's N terminus. B. subtilis spores lacking the gerF (lgt) gene that codes for prelipoprotein diacylglycerol transferase exhibited significantly slowed germination in response to nutrient germinants as found previously, but germination of gerF spores with a mixture of Ca2+ and dipicolinic acid or with dodecylamine was normal, as was the spontaneous germination of gerF spores lacking all nutrient germinant receptors. The deleterious effects of the gerF mutation on nutrient germination were highest on germination triggered by the GerA nutrient receptor and were less so (but still significant) on germination triggered by the GerB nutrient receptor. However, there was little, if any, effect on GerK nutrient receptor-mediated spore germination. As predicted from the latter results, replacement by alanine of the cysteine residue to which diacylglycerol is thought to be added to these nutrient receptors had a large effect on GerA receptor function, less effect on GerB receptor function, and little, if any, effect on GerK receptor function.