Family C104


Summary Holotypes Alignment Tree Genomes Structure Literature

Summary for family C104

Family type peptidaseC104.001 - PlyC phage lysin (Streptococcus phage C1), MEROPS Accession MER0428985 (peptidase unit: 309-465)
Content of familyFamily C104 contains bacterial cell-wall degrading cysteine peptidases
History Identifier created: MEROPS 9.11 (21 July 2014)
Lysins release viral progeny from host cells by degrading the murein of the bacterial cell wall. The lysin PlyC (C104.001) is derived from bacteriophage C(1) which infects Streptococcus species (Nelson et al., 2006). PlyC
Catalytic typeCysteine
Active site residuesC333 H420 
Active siteCys333 and His420 in the PlyCA subunit have been identified as the catalytic dyad by site-directed mutagenesis (Nelson et al., 2006).
Activities and specificitiesA related lysin specific for Streptococcus pyogenes, known as PlyPy (C104.002), has been characterized (Lood et al., 2014) and has been shown to cleave the cell-wall crosslinking peptide at the D-Ala+Ala bond.
InhibitorsInhibition by dithiodipyridine, N-ethylmaleimide and iodoacetamide has been shown (Nelson et al., 2006).
Molecular structurePlyC lysin is a heteromer consisting of eight PlyCB subunits and one PlyCA subunit (Nelson et al., 2006). PlyCA contains the catalytic domain and PlyCB is required for binding to the bacterial cell wall (Nelson et al., 2006). From the solved tertiary structure, a PlyCA subunit is attached to eight PlyCB subunits arranged in a ring and each PlyCB subunit has a cleft for binding the cell wall (McGowan et al., 2012). The tertiary structure of PlyCA shows that in addition to a CHAP-like lysin domain, the protein also contains a glycosyl hydrolase domain and a docking domain (McGowan et al., 2012). Family C104 is included in clan CA because the structure of plyCA resembles that of papain (C01.001).
Distribution of family Bacteria details  
Archaea -  
Protozoa -  
Fungi -  
Plants -  
Animals -  
Viruses details  
Biological functionsPlyC lysin releases viral progeny from an infected bacterium by degrading the cell wall.
Pharmaceutical and biotech relevanceBecause PlyC rapidly degrades bacterial cell walls it has been used to destroy biofilms of Streptococcus pyogenes (Shen et al., 2013).
Statistics for family C104Sequences:27
Identifiers with PDB entries:1
Downloadable files Sequence library (FastA format)
Sequence alignment (FastA format)
Phylogenetic tree (Newick format)
Peptidases and Homologues MEROPS ID Structure
PlyC phage lysinC104.001Yes
PlyPy phage lysinC104.002-
family C104 unassigned peptidasesunassigned-