FIG. 3.

Multiple alignment of a putative tail fiber protein from S. thermophilus phages showing distinct host ranges. The proteins are identified with their corresponding codon lengths. Gaps (−) were introduced for maximal alignment. Amino acid positions that differ in the corresponding proteins from phages Sfi19 and Sfi21 are underlined, and the location of a spontaneous deletion in the Sfi21 protein is marked by bent arrows. Amino acid positions which are identical in at least three proteins are shaded.