Selective Ligand Recognition by a Diversity-Generating Retroelement Variable Protein
Figure 1
Tropism and Receptor Specificities of Bordetella Bacteriophages
(A) The Mtd-P1 variant is expressed by BPP-1 phage and sets the tropism of the phage to Bvg+ Bordetella due to recognition of the Bvg+-specific receptor pertactin. The Mtd-M1 variant is a direct descendant of Mtd-P1 and is expressed by BMP-1 phage. It sets tropism to Bvg– Bordetella through recognition of an unidentified receptor. Mtd-M1 also binds pertactin, albeit nonproductively. The Mtd-P6 variant is a direct descendant of Mtd-M1 and is expressed by BPP-6 phage. It sets the tropism of BPP-6 to Bvg+ Bordetella due to recognition of pertactin.
(B) Variable region sequences of Mtd-P1, Mtd-M1, and Mtd-P6. Variable residues are in color, and invariant residues in black. For Mtd-P1, variable residues are in blue. For Mtd-M1, variable residues in common with Mtd-P1 are in blue, and those unique to Mtd-M1 are in green. For Mtd-P6, residues in common with Mtd-M1 or Mtd-P1 are in green or blue, respectively, and those unique to Mtd-P6 are in red. Mtd has 381 residues in total.