Glutamyl endopeptidase I is a family of extracellular
bacteria
Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among ...
l
serine proteases. The proteases within this family have been identified in species of ''
Staphylococcus
''Staphylococcus'' is a genus of Gram-positive bacteria in the family Staphylococcaceae from the order Bacillales. Under the microscope, they appear spherical (cocci), and form in grape-like clusters. ''Staphylococcus'' species are facultative ...
'', ''
Bacillus'', and ''
Streptomyces
''Streptomyces'' is the largest genus of Actinomycetota and the type genus of the family Streptomycetaceae. Over 500 species of ''Streptomyces'' bacteria have been described. As with the other Actinomycetota, streptomycetes are gram-positive, ...
'', among others. The two former are more closely related, while the ''Streptomyces''-type is treated as a separate family,
glutamyl endopeptidase II.
Identified proteases
''Staphylococcus''
* ''
S. aureus''
glutamyl endopeptidase GluV8
: The first discovered enzyme of this family, and the most well characterized, was isolated from the ''
Staphylococcus aureus
''Staphylococcus aureus'' is a Gram-positive spherically shaped bacterium, a member of the Bacillota, and is a usual member of the microbiota of the body, frequently found in the upper respiratory tract and on the skin. It is often positive ...
'' strain V8, and hence better known as "V8 protease". Other common references to this protease are staphylococcal serine protease, and SspA from its corresponding gene.
* ''
S. epidermidis'' glutamyl endopeptidase GluSE
: Also called ''S. epidermidis'' serine protease (Esp).
* ''
S. warneri'' glutamyl endopeptidase GluSW
: Also referred to as PROM.
''Bacillus''
* ''B. licheniformis'' glutamyl endopeptidase GluBL
* ''
B. subtilis
''Bacillus subtilis'', known also as the hay bacillus or grass bacillus, is a Gram-positive, catalase-positive bacterium, found in soil and the gastrointestinal tract of ruminants, humans and marine sponges. As a member of the genus ''Bacillus' ...
'' glutamyl endopeptidase GluBS
''
Enterococcus''
* ''
E. faecalis
''Enterococcus faecalis'' – formerly classified as part of the group D ''Streptococcus'' system – is a Gram-positive, commensal bacterium inhabiting the gastrointestinal tracts of humans. Like other species in the genus ''Enterococcus'', ''E ...
'' glutamyl endopeptidase SprE
Function
Glutamyl endopeptidase is in at least some species part of a
zymogen
In biochemistry, a zymogen (), also called a proenzyme (), is an inactive precursor of an enzyme. A zymogen requires a biochemical change (such as a hydrolysis reaction revealing the active site, or changing the configuration to reveal the active ...
activation cascade, with its activity being dependent on proteolytic activation of a pre-form of the protease. GluV8 of ''S. aureus'', for example, is dependent of activation by the
metalloprotease aureolysin
Aureolysin (, ''protease III, staphylococcal metalloprotease,'' ''Staphylococcus aureus neutral proteinase'') is an extracellular metalloprotease expressed by ''Staphylococcus aureus''. This protease is a major contributor to the bacterium's virule ...
, and is itself needed for activation of staphopain B. GluSE, GluSW and SprE have been observed to be activated by a metalloprotease in a similar fashion.
Proteases of this group hydrolyzes peptide bonds after the negatively charged glutamic acid or aspartic acid, with a higher preference to the former. The pH optimum has been found to lie slightly above neutral pH (7-8) for GluV8 and GluBL.
It has been shown that in spite of their similarities, the proteases from different species may differ in their efficiency in cleaving biological targets. The GluV8 is suggested in several mechanisms of ''S. aureus'' immune evasion, and GluV8 and GluSE have shown impact on the regulation of
biofilm
A biofilm comprises any syntrophic consortium of microorganisms in which cells stick to each other and often also to a surface. These adherent cells become embedded within a slimy extracellular matrix that is composed of extracellular ...
s.
See also
*
Proteolysis
Proteolysis is the breakdown of proteins into smaller polypeptides or amino acids. Uncatalysed, the hydrolysis of peptide bonds is extremely slow, taking hundreds of years. Proteolysis is typically catalysed by cellular enzymes called protease ...
References
External links
* ''Staphylococcus aureus''
glutamyl endopeptidaseat Universal Protein Resource (UniProt).
* ''Bacillus licheniformis'
glutamyl endopeptidaseat Universal Protein Resource (UniProt).
EC 3.4.21
Proteases
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