Diverse Reductive Dehalogenases Are Associated with Clostridiales-Enriched Microcosms Dechlorinating 1,2-Dichloroethane

Figure 5

Amino acid alignment of the DcaA proteins of the new identified RDs, with those previously identified in the groundwater (RD-54: AM183919) and in D. dichloroeliminans strain DCA1 (D. d. DCA1: AM183918), with PceA of Desulfitobacterium sp. strain Y51 (D. Y51: AY706985), D. hafniense strain TCE1 (D. h.: AJ439608), and D. restrictus strain DSMZ 9455T (D. r.: AJ439607) and with the WL rdhA1 (FJ010189). Black line (blocks A and B) rectangles indicate two amino acid stretches where 53% of the total amino acid diversity resides between DcaA and PceA [16]. Within blocks A and B of the selected RDs sequences, as well in other smaller regions of the DcaA subunit, it was possible to identify amino acids specific for (i) PceA of the PCE-RDs (black residues in a light gray background), (ii) DcaA of group I, specific for WL rdhA1 and for the reductive dehalogenases identified in the low aquifer after the lactate treatment (white residues in a light gray background), (iii) those of group II proposed to be specific for 1,2-DCA RDs from Desulfitobacterium (black residues in a dark gray background), (iv) and finally those common to all the RDs within groups I and II but not conserved in the PCE-specific RDs (white residues in a black background). Asterisks, colons, and dots below the alignment indicate an identical position in all the proteins, a position with a conservative substitution, and a position with a semiconservative substitution, respectively.