Cloning and nucleotide sequence of the gene encoding arginine deiminase of Mycoplasma arginini

The existence of a mycoplasmal arginine deiminase which catalyzes the conversion of L-arginine to L-citrulline has been postulated. Here we show the partial amino acid sequence of arginine deiminase of Mycoplasma arginini and the complete nucleotide sequence of the arginine deiminase gene of M. arginini. The open reading frame deduced from this sequence consists of 1,230 bp encoding 410 amino acids. The mature form of this enzyme contains 409 amino acids after the deletion of the first methionine. In this open reading frame, TGA nonsense codons are used as tryptophan codons; this usage was verified by determination of the amino acid sequence. The molecular weight of the enzyme calculated from the deduced amino acid sequence is 46,372. Recently, the nucleotide sequence of the arginine deiminase gene of M. arginini was reported by Kondo et al. (K. Kondo, H. Sone, H. Yoshida, T. Toida, K. Kanatani, Y.-M. Hong N. Nishino, and J. Tanaka, Mol. Gen. Genet. 221:81-86, 1990). However, their sequence differed from ours in several places and especially at the C terminus.