Table 3. Membership composition of Tryptophan Cohesion Groups^a

TCG-1	[Corynebacterium diptheriae]^b *[Corynebacterium glutamicum]^b* *Escherichia coli* *Haemophilus influenzae* *[Helicobacter pylori]^b* *Shewanella putrefaciens* *Vibrio cholerae* Actinobacillus actinomycetemcomitans Buchnera aphidicola^c Blochmannia floridanus^c [Corynebacterium efficiens]^b Erwinia carotovora Klebsiella pneumoniae Pasteurella multocida Photorhabdus luminescens Salmonella enterica Shigella flexneri Vibrio parahaemolyticus Vibrio vulnificus Yersinia pestis
TCG-2^d	*Burkholderia fungorum* *Methylococcus capsulatus* *Neisseria meningitidis* *Nitrosomonas europaea* Pseudomonas aeruginosa* Pseudomonas syringae* *Ralstonia metallidurans* *Thiobacillus ferrooxidans* *Xanthomonas campestris* *Xylella fastidiosa* Acinetobacter sp. Azotobacter vinelandii* Bordetella bronchisepticum Bordetella parapertussis Bordetella pertussis Burkholderia cepacia Burkholderia multivorans Chromobacterium violaceum Microbulbifer degradans Neisseria gonorrhoeae Pseudomonas fluorescens* Pseudomonas putida* Psychrobacter sp. Ralstonia solanacearum Xanthomonas axonopodis
TCG-3	*Caulobacter crescentus* *Rhodobacter sphaeroides* *Sphingomonas aromaticivorans* Agrobacterium tumefaciens Bradyrhizobium japonicum Brucella melitensis Brucella suis Rhizobium loti Rhodopseudomonas palustris Sinorhizobium meliloti
TCG-4	*Anabaena* (Nostoc) sp. PCC 7120 *Nostoc punctiforme* *Prochlorococcus marinus* CCMP 1986 (MED4) *Synechococcus* sp. WH8102 *Synechocystis* sp. PCC 6803 Anabaena variabilis ATCC 29413 Crocosphaera watsonii WH 8501 Gloeobacter violaceus PCC 2471 Prochlorococcus marinus CCMP1375 (SS120) Prochlorococcus marinus MIT9313 Synechococcus elongatus PCC 7942 Thermosynechococcus elongatus BP-1 Tricodesmium erythraeum
TCG-5^e	*Streptomyces coelicolor* *Mycobacterium tuberculosis* *Thermomonospora fusca* Bifidobacterium longum Mycobacterium avium Mycobacterium bovis Mycobacterium leprae Mycobacterium smegmatis Streptomyces avermitilis
TCG-6	*Bacillus halodurans* Bacillus stearothermophilus Bacillus subtilis Oceanobacillus iheyensis
TCG-7	*Bacillus anthracis* *Lactococcus lactis* *Listeria monocytogenes* *Staphylococcus aureus* *Streptococcus pneumoniae* Bacillus cereus Listeria innocua Staphylococcus epidermidis Streptococcus gordonii Streptococcus mutans
^aEach tryptophan cohesion group (TCG) defined by the concatenated tree for Trp proteins (Fig. 2) is congruent with the color-coded subtree section within the 16S rRNA tree (Fig. 1). Organisms that are included in the concatenated tree of Fig. 2 are indicated in regular type, whereas additional organisms not included in the concatenated tree but that were qualitatively determined to belong to a given TCG are indicated in boldface type. ^bTCG members originating by LGT are indicated within brackets and indented. ^cInsect symbionts. ^dThe five organisms marked with asterisks form a distinctive subclade that is, in fact, not a "pure" component of TCG-2 because of the LGT origins of trpEa and trpEb from TCG-3 (see text). ^eAll members of TCG-5 lack trpC and presumably utilize a dual-pathway hisA (priA) for this function.