S
IPR001969

Aspartic peptidase, active site

InterPro entry
Short nameAspartic_peptidase_AS

Description

This signature contains the active site residues which are conserved in eukaryotic and viral aspartyl proteases.

Aspartic peptidase, also known as aspartyl proteases (
3.4.23.-
) are a widely distributed family of proteolytic enzymes
[5, 10, 2]
known to exist in vertebrates, fungi, plants, retroviruses and some plant viruses. Aspartate proteases of eukaryotes are monomeric enzymes which consist of two domains. Each domain contains an active site centred on a catalytic aspartyl residue. The two domains most probably evolved from the duplication of an ancestral gene encoding a primordial domain. Currently known eukaryotic aspartyl proteases are:


 * Vertebrate gastric pepsins A and C (also known as gastricsin). Vertebrate chymosin (rennin), involved in digestion and used for making cheese.
 * Vertebrate lysosomal cathepsins D (EC 3.4.23.5) and E (EC 3.4.23.34).
 * Mammalian renin (EC 3.4.23.15) whose function is to generate angiotensin I from angiotensinogen in the plasma.
 * Fungal proteases such as aspergillopepsin A (EC 3.4.23.18), candidapepsin (EC 3.4.23.24), mucoropepsin (EC 3.4.23.23) (mucor rennin), endothiapepsin (EC 3.4.23.22), polyporopepsin (EC 3.4.23.29), and rhizopuspepsin (EC 3.4.23.21).
 * Yeast saccharopepsin (EC 3.4.23.25) (proteinase A) (gene PEP4). PEP4 is implicated in posttranslational regulation of vacuolar hydrolases.
 * Yeast barrierpepsin (EC 3.4.23.35) (gene BAR1); a protease that cleaves alpha-factor and thus acts as an antagonist of the mating pheromone.
 * Fission yeast sxa1 which is involved in degrading or processing the mating pheromones.


Aspartic peptidases, also known as aspartyl proteases (
3.4.23.-
), are widely distributed proteolytic enzymes
[5, 10, 2]
known to exist in vertebrates, fungi, plants, protozoa, bacteria, archaea, retroviruses and some plant viruses. All known aspartic peptidases are endopeptidases. A water molecule, activated by two aspartic acid residues, acts as the nucleophile in catalysis. Aspartic peptidases can be grouped into five clans, each of which shows a unique structural fold
[9]
.


 * Peptidases in clan AA are either bilobed (family A1 or the pepsin family) or are a homodimer (all other families in the clan, including retropepsin from HIV-1/AIDS)
[7]
. Each lobe consists of a single domain with a closed β-barrel and each lobe contributes one Asp to form the active site. Most peptidases in the clan are inhibited by the naturally occurring small-molecule inhibitor pepstatin
[11]
.
 * Clan AC contains the single family A8: the signal peptidase 2 family. Members of the family are found in all bacteria. Signal peptidase 2 processes the premurein precursor, removing the signal peptide. The peptidase has four transmembrane domains and the active site is on the periplasmic side of the cell membrane. Cleavage occurs on the amino side of a cysteine where the thiol group has been substituted by a diacylglyceryl group. Site-directed mutagenesis has identified two essential aspartic acid residues which occur in the motifs GNXXDRX and FNXAD (where X is a hydrophobic residue)
[13]
. No tertiary structures have been solved for any member of the family, but because of the intramembrane location, the structure is assumed not to be pepsin-like.
 * Clan AD contains two families of transmembrane endopeptidases: A22 and A24. These are also known as "GXGD peptidases" because of a common GXGD motif which includes one of the pair of catalytic aspartic acid residues. Structures are known for members of both families and show a unique, common fold with up to nine transmembrane regions
[3]
. The active site aspartic acids are located within a large cavity in the membrane into which water can gain access
[6]
.
 * Clan AE contains two families, A25 and A31. Tertiary structures have been solved for members of both families and show a common fold consisting of an α-β-α sandwich, in which the β sheet is five stranded
[8, 4]
.
 * Clan AF contains the single family A26. Members of the clan are membrane-proteins with a unique fold. Homologues are known only from bacteria. The structure of omptin (also known as OmpT) shows a cylindrical barrel containing ten β strands inserted in the membrane with the active site residues on the outer surface
[1]
.
 * There are two families of aspartic peptidases for which neither structure nor active site residues are known and these are not assigned to clans. Family A5 includes thermopsin, an endopeptidase found only in thermophilic archaea. Family A36 contains sporulation factor SpoIIGA, which is known to process and activate sigma factor E, one of the transcription factors that controls sporulation in bacteria
[12]
.

References

1.Crystal structure of the outer membrane protease OmpT from Escherichia coli suggests a novel catalytic site. Vandeputte-Rutten L, Kramer RA, Kroon J, Dekker N, Egmond MR, Gros P. EMBO J. 20, 5033-9, (2001). View articlePMID: 11566868

2.Structural and evolutionary relationships between retroviral and eucaryotic aspartic proteinases. Rao JK, Erickson JW, Wlodawer A. Biochemistry 30, 4663-71, (1991). View articlePMID: 1851433

3.The crystal structure of GXGD membrane protease FlaK. Hu J, Xue Y, Lee S, Ha Y. Nature 475, 528-31, (2011). View articlePMID: 21765428

4.Crystal structure of a novel germination protease from spores of Bacillus megaterium: structural arrangement and zymogen activation. Ponnuraj K, Rowland S, Nessi C, Setlow P, Jedrzejas MJ. J. Mol. Biol. 300, 1-10, (2000). View articlePMID: 10864493

5.Gastric proteinases--structure, function, evolution and mechanism of action. Foltmann B. Essays Biochem. 17, 52-84, (1981). PMID: 6795036

6.Structure of a presenilin family intramembrane aspartate protease. Li X, Dang S, Yan C, Gong X, Wang J, Shi Y. Nature 493, 56-61, (2013). View articlePMID: 23254940

7.X-ray analysis of HIV-1 proteinase at 2.7 A resolution confirms structural homology among retroviral enzymes. Lapatto R, Blundell T, Hemmings A, Overington J, Wilderspin A, Wood S, Merson JR, Whittle PJ, Danley DE, Geoghegan KF. Nature 342, 299-302, (1989). View articlePMID: 2682266

8.Crystal structure of the hydrogenase maturating endopeptidase HYBD from Escherichia coli. Fritsche E, Paschos A, Beisel HG, Bock A, Huber R. J. Mol. Biol. 288, 989-98, (1999). View articlePMID: 10331925

9.Evolutionary families of peptidases. Rawlings ND, Barrett AJ. Biochem. J. 290 ( Pt 1), 205-18, (1993). View articlePMID: 8439290

10.The structure and function of the aspartic proteinases. Davies DR. 19, 189-215, (1990). PMID: 2194475

11.Pepstatin, a new pepsin inhibitor produced by Actinomycetes. Umezawa H, Aoyagi T, Morishima H, Matsuzaki M, Hamada M. J. Antibiot. 23, 259-62, (1970). PMID: 4912600

12.A two-compartment bioreactor system made of commercial parts for bioprocess scale-down studies: impact of oscillations on Bacillus subtilis fed-batch cultivations. Junne S, Klingner A, Kabisch J, Schweder T, Neubauer P. Biotechnol J 6, 1009-17, (2011). View articlePMID: 21751400

13.The potential active site of the lipoprotein-specific (type II) signal peptidase of Bacillus subtilis. Tjalsma H, Zanen G, Venema G, Bron S, van Dijl JM. J. Biol. Chem. 274, 28191-7, (1999). View articlePMID: 10497172

GO terms

biological process

cellular component

  • None

Cross References

Contributing Member Database Entry
This website requires cookies, and the limited processing of your personal data in order to function. By using the site you are agreeing to this as outlined in our Privacy Notice and Terms of Use.