The amino acid sequence of an extracellular nuclease of Staphylococcus aureus. 3. Complete amino acid sequence.

In a previous paper data were presented that permitted the linear arrangement of five fragments produced by cleavage of an extracellular nuclease of Staphylococcus aureus with cyanogen bromide (1). The amino acid sequences of the tryptic peptides prepared from these fragments, together with the partial sequences of chymotryptic peptides isolated from digests of the intact nuclease, have also been presented (2). In the present communication, the tryptic peptides derived from each cyanogen bromide fragment are arranged in linear order on the basis of the amino acid sequences of the tryptic and chymotryptic cleavage products. In order to obtain supplemental information necessary for final alignment, certain tryptic fragments of trifluoroacetylated nuclease were separated and examined. The molecular weight calculated from the deduced sequence is consistent with estimates obtained from physicochemical examination (3) and from s-ray diffraction studies (4).