Family M98


Summary Holotypes Alignment Tree Genomes Literature H-seq M-seq

Summary for family M98

Family type peptidaseM98.001 - YghJ g.p. (Escherichia coli) (Escherichia coli), MEROPS Accession MER0018771 (peptidase unit: 1081-1381)
Content of familyFamily M98 contains metallopeptidases
History Identifier created: MEROPS 9.10 (20 December 2013)
Enterotoxigenic Escherichia coli is the causative agent for a diarrheal illness in young children which is a leading cause of death in developing countries. The YghJ protein is a secreted antigen that is required for the delivery of a heat-labile toxin to the small intestinal enterocytes (Luo et al., 2014). Deletion of the yghJ gene results in increased accumulation of mucins at the surface of the bacterium (Luo et al., 2014).
Catalytic typeMetallo
Active site residuesH1303 E1304 H1307 E1321 
Active siteAn HEXXH zinc-binding motif is present and conserved amongst homologues. The histidines are presumed to be metal ligands and the glutamic acid to be an active site residue. Surprisingly, deletion of a 22-residue section including the HEXXH motif or site-directed mutagensis of individual residues in this motif only partially suppressed mucin degradation (Luo et al., 2014).
Activities and specificitiesThe YghJ protein from Escherichia coli has been shown to cleave the mucins Muc2 and Muc3 (Luo et al., 2014).
InhibitorsInhibition of mucin degradation by EDTA and o-phenanthroline have been shown (Luo et al., 2014).
Molecular structureThe YghJ protein is multidomain. It has an N-terminal signal peptide, followed by a potential lipoprotein motif, a domain of unknown function, and a metallopeptidase domain at the C-terminus (Luo et al., 2014). The metallopeptidase domain has been described as 'M60-like' (Nakjang et al., 2012).
Distribution of family Bacteria details  
Archaea -  
Protozoa details  
Fungi -  
Plants details  
Animals details  
Viruses -  
Biological functionsThe YghJ protein is important for bacterial invasion of the small intestine and degrades surface mucins. Removal of surface mucins such as Muc2 may allow a heat-labile toxin to bind to the surface of intestinal enterocytes (Luo et al., 2014). The heat labile toxin A chain activates intracellular adenyl cyclase by catalyzing the ADP-ribosylation of the GTP binding protein of adenyl cyclase (<%Tsuji et al., 1990[]%>).
Statistics for family M98Sequences:403
Identifiers with PDB entries:0
Downloadable files Sequence library (FastA format)
Sequence alignment (FastA format)
Phylogenetic tree (Newick format)
Peptidases and Homologues MEROPS ID Structure
YghJ g.p. (Escherichia coli)M98.001-
LOC100535908 g.p. (Brachydanio rerio)M98.A01-
LOC100535998 g.p. (Brachydanio rerio)M98.A02-
family M98 non-peptidase homologuesnon-peptidase homologue-
family M98 unassigned peptidasesunassigned-