Phylogenetic trees of the α subunits (a), β subunits
(b), and reductases (c) of known and putative class IB DOs. Also
included were two α subunit components from different ARHDO classes
(Table 1): NDO (NdoB, class III, M23914 [27]) and
phthalate DO (Pht3, class IA, D13229 [34]). An outgroup
(Pht3) was used only for panel a. Abbreviations: Abs,
2-aminobenzenesulfonate DO of Alcaligenes sp. strain
AF109074) (29); Ant, AntDO of Acinetobacter sp.
strain ADP1 (6); Ant(Pa), putative sequence of P.
aeruginosa PAO1; Ben, BenDO of Acinetobacter sp. strain
ADP1 (32); Ben(Pa), putative sequence of P.
aeruginosa PAO1; Ben(Pp), sequence of P. putida PRS2000
(8); Cbd, 2-halobenzoate 1,2-DO of B. cepacia
(X79076 [16]); Tft, 2,4,5-trichlorophenoxyacetic acid
oxygenase of B. cepacia (U11420 [9]); Xyl,
toluate 1,2-DO of P. putida (PIR A41659
[17]). The numbers at branch points indicate the
confidence (in percent) as determined by bootstrap analysis with 100
replicates. The scale bar indicates the relative phylogenetic distances
measured as number of amino acid substitutions per site.