Plasmepsin

From Wikipedia, the free encyclopedia
Plasmepsin I
Identifiers
EC number 3.4.23.38
CAS number 180189-87-1
Databases
IntEnz IntEnz view
BRENDA BRENDA entry
ExPASy NiceZyme view
KEGG KEGG entry
MetaCyc metabolic pathway
PRIAM profile
PDB structures RCSB PDB PDBe PDBsum
Plasmepsin II

Plasmepsin II complexed with
inhibitor pepstatin A.[1]
Identifiers
EC number 3.4.23.39
CAS number 159447-18-4
Databases
IntEnz IntEnz view
BRENDA BRENDA entry
ExPASy NiceZyme view
KEGG KEGG entry
MetaCyc metabolic pathway
PRIAM profile
PDB structures RCSB PDB PDBe PDBsum

Plasmepsins are a class of at least 10 enzymes (EC 3.4.23.38 and EC 3.4.23.39) produced by the Plasmodium falciparum parasite. There are ten different isoforms of these proteins and ten genes coding them respectively in Plasmodium (Plm I, II, III, IV, V, VI, VII, IX, X and HAP). It has been suggested that the plasmpesin family is smaller in other human Plasmodium species. Expression of Plm I, II, IV, V, IX, X and HAP occurs in the erythrocytic cycle, and expression of Plm VI, VII, VIII, occurs in the exoerythrocytic cycle. Through their haemoglobin-degrading activity, they are an important cause of symptoms in malaria sufferers. Consequently this family of enzymes is a potential target for antimalarial drugs.

Plasmepsins are aspartic acid proteases, meaning their active site contains two aspartic acid residues. These two aspartic acid residue act respectively as proton donor and proton acceptor, catalysing the hydrolysis of peptide bond in proteins.

There are four types of plasmepsins, closely related but varying in the specificity of cleavage site. Plasmepsins I and II cleave hemoglobin between residues Phenylalanine 33 and Leucine 34 of α-globin subunit.

The name plasmepsin may come from Plasmodium (the organism) and pepsin (a common aspartic acid protease with similar molecular structure).

The closest (non-pathogenic) enzymatic equivalent in humans is the beta-secretase enzyme.

References

  1. ↑ PDB 1SME; Silva AM, Lee AY, Gulnik SV, Maier P, Collins J, Bhat TN, Collins PJ, Cachau RE, Luker KE, Gluzman IY, Francis SE, Oksman A, Goldberg DE, Erickson JW (September 1996). "Structure and inhibition of plasmepsin II, a hemoglobin-degrading enzyme from Plasmodium falciparum". Proc. Natl. Acad. Sci. U.S.A. 93 (19): 10034–9. doi:10.1073/pnas.93.19.10034. PMC 38331. PMID 8816746. 

Further reading

  • Dame JB, Reddy GR, Yowell CA, Dunn BM, Kay J, Berry C (1994). "Sequence, expression and modeled structure of an aspartic proteinase from the human malaria parasite Plasmodium falciparum". Mol. Biochem. Parasitol. 64 (2): 177–90. doi:10.1016/0166-6851(94)90024-8. PMID 7935597. 
  • Bernstein NK, Cherney MM, Loetscher H, Ridley RG, James MN (1999). "Crystal structure of the novel aspartic proteinase zymogen proplasmepsin II from plasmodium falciparum". Nat. Struct. Biol. 6 (1): 32–7. doi:10.1038/4905. PMID 9886289. 

External links

Proteases: aspartic acid proteases (EC 3.4.23)
Vertebrate
Pathogenic
Plant
Cathepsin
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