Nature 388, 539–547 (1997)

In this Article, we incorrectly stated that the amino acids lysine and arginine are twice as abundant in H. pylori proteins as they are in those of Haemophilus influenzae and Escherichia coli. This statement was derived from amino-acid analyses that compared absolute differences in abundance, but these do not reflect the frequencies with which amino acids are found in the organisms in question. The actual abundance of arginine in H. pylori, H. influenzae and E. coli is 3.5, 4.5 and 5.5%, respectively; the abundance of lysine in these organisms is 8.9, 6.3 and 4.4%, respectively. This oversight is particularly unfortunate because Russell H. Doolittle, who wrote an accompanying News and Views on our Article and brought this to our attention, was led to comment on the significance of our inaccurate observation. We regret this and any other misunderstanding that our error may have caused.