FIG. 5.

Alignment of the two PAS domains from PpsR, CrtJ, and several representative signal transduction proteins from the proteobacteria. A portion of the alignment was taken from the World Wide Web (http://www.llu.edu/llu/medicine/micro/PAS/paslist.htm) (28) and modified. Consensus derived from the alignment of several hundred PAS domains (28) is shown below the alignment. Identical amino acids, i.e., those conserved in at least 50% of sequences, are shown in reverse contrast. Similar residues present in at least 75% of sequences are shaded. Designation of residues: c, charged (DEHKR), u, bulky hydrophobic (FILMVWY), h, hydrophobic (ACFGILMTVWY); o, hydroxy (ST); p, polar (CDEHKNQRST); t, turn-like (ACDEGHNQRST); s, small (ACDGNPSTV).