TABLE 3.

Results of sortase-substrate predictions

Prediction methoda or categoryNo. of predicted sortase-substrate linkagesb% of total substrates
Single sortasec145 (153)17.1
Single sortase A-single sortase Bd257 (257)28.8
Single sortase-single substrate genomic clustere23 (31)3.5
Single sortase and single sortase-single substrate genomic cluster8 (8)<1.0
Sequence homologyf163 (411)46.0
Subfamily-4 sorting signal specificity—LPXTA CWSg14 (24)2.7
Subfamily-5 sorting signal specificity—LAXTG CWS42 (46)5.2
    Subtotal65273.0
Genomic cluster with single sortase and multiple substratesh37 (52)5.8
    Subtotal68977.2
Unassigned substrates20322.8
    Total no. of CWS-containing proteins892100
  • a General description of method used to link a CWS-containing substrate to a sortase homolog.

  • b First number is the sum of nonredundant linkages; i.e., linkages predicted exclusively from this method. Number in parentheses is the sum total of linkages made by prediction method, which might include predictions made by more than one method.

  • c Genome has only one sortase homolog.

  • d Genome has only one sortase A homolog and one sortase B homolog.

  • e Genome has one sortase homolog genomically clustered with one CWS-containing protein.

  • f Predictions of sortase-substrate linkages are based on sequence homology between a CWS-containing protein in one species and a CWS-containing protein(s) that has been assigned by one of the above three methods.

  • g Predictions of sortase-substrate linkages are based on the sorting signals of the CWS-containing proteins. Subfamily-4 sortases are predicted to process CWS-containing proteins with an LPXTA motif, whereas subfamily-5 sortases are predicted to process CWS-containing proteins with a LAXTG motif.

  • h Genome has only one sortase homolog that is genomically clustered with two or more CWS-containing proteins (number of predictions excludes SrtB genomic clusters and subfamily-5 substrate in C. diphtheriae).