Dynamic diversity of the tryptophan pathway in chlamydiae: reductive evolution and a novel operon for tryptophan recapture

Table 3 GC content of trpR genes compared to the GC content of the corresponding genomes

	%GC
Organism	Genome	trpR
Chlamydia psittaci	42	37
Chlamydia trachomatis D	42	37
Escherichia coli	51	54
Salmonella typhimurium	55	54
Haemophilus influenzae	38	36
Vibrio cholerae	48	50
Enterobacter aerogenes	61	58
Yersinia pestis	50	51
Yersiniapseudotuberculosis	43	50
Pasteurella multocida	38	43
Actinobacillus actinomycetemcomitans	39	44
Xylella fastidiosa ^*	54	34
Enterobacter cloacae	56	58

^*trpR from X. fastidiosa has been found to be part of a low-GC block of genes, for which there is strong evidence for lateral gene transfer (G.X., C.A.B., N. Keyhani, and R.A.J., unpublished observations).

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