Incorporation of 5-methyl- and 5-hydroxy-tryptophan into the protein of Bacillus subtilis

Addition of the tryptophan analogues 5-methyl-tryptophan, 5-hydroxy-tryptophan, and 7-aza-tryptophan, during tryptophan starvation of a tryptophan auxotroph of Bacillus subtilis, stimulated amino acid incorporation. Two of the analogues tested, 5-methyl-tryptophan and 5-hydroxy-tryptophan, competed with each other, but their addition did not prevent tryptophan incorporation into acid-insoluble material. The incorporation of tryptophan and 5-hydroxy-tryptophan was stimulated when a mixture of phenylalanine and tyrosine was present in the medium. The two analogues 5-methyl-tryptophan and 5-hydroxy-tryptophan were recovered in protein hydrolysates of analogue-grown cultures, and there is evidence suggesting that the analogues are not chain terminators. Neither analogue prevented the polysome degradation that occurs during tryptophan starvation.