The FK phages appear to have FOUR genes in the left arm that encode four distinct enzymes involved in cell wall metabolism. Example: Elver genes 8, 9, 10, 11. Gene 8 encodes the M23 peptidase activity associated with the endolysin (lysin A) and has high coverage to HHpred hits. Thus, a lysin A annotation is warranted here. Gene 9 encodes a hyaluronoglucosaminidase, often referred to as hyaluronidase an enzyme that degrades hyaluronic acid (HA). This activity can be found associated with minor tails in some phages. Best annotation call here is a hydrolase. Gene 10 encodes a polysaccharide deacetylase that is an esterase that catalyze the hydrolysis of ester bonds, in this case, acetyl groups attached to polysaccharides. Gene 11 encodes another peptidase, but does not show full coverage in HHpred and also does not have a defined lysin Alike domain activity (example M23, etc.), thus, best annotation is peptidase. Its likely that all of these work together to lyse the cell wall and more defined annotation of activities might be possible in later annotations, so always check Official functions list for updates on the lysin A annotation.
RS Pollenz