Leishmanolysin

 

Leishmania is a protozoan parasite transmitted from sandfly vector to human and other mammalian hosts causing chronic infections. It exists as extracellular promastigotes within sandflies and intracellular amastigotes within macrophage cells of mammals. Leishmanolysin is the major protein component of the Leishmania promastigote surface. It is characterised as a zinc metalloproteinase containing a glycosyl phosphatidyl inositol membrane anchor. It is an endopeptidase cleaving a variety of substrate. Its role in the life cycle Leishmania remains to be established.

 

Reference Protein and Structure

Sequence
P08148 UniProt (3.4.24.36) IPR001577 (Sequence Homologues) (PDB Homologues)
Biological species
Leishmania major (Leishmania) Uniprot
PDB
1lml - LEISHMANOLYSIN (1.86 Å) PDBe PDBsum 1lml
Catalytic CATH Domains
3.10.170.20 CATHdb 3.90.132.10 CATHdb (see all for 1lml)
Cofactors
Zinc(2+) (1)
Click To Show Structure

Enzyme Reaction (EC:3.4.24.36)

water
CHEBI:15377ChEBI
+
Tyr-Leu
CHEBI:75003ChEBI
tyrosine
CHEBI:18186ChEBI
+
leucine
CHEBI:25017ChEBI
Alternative enzyme names: Leishmania metalloproteinase, Glycoprotein gp63, Promastigote surface endopeptidase, Promastigote surface protease, Surface acid proteinase,

Enzyme Mechanism

Introduction

Leishmanolysin consists of HEXXH motif which is common in all zinc metalloproteinase, so it was proposed that it shares the same mechanism as the other zinc metalloproteinases such as thermolysin. Glu265, acting in conjunction with Zn2+ ion to deprotonate and activate a water molecule. The activated water molecule acts as a nucleophile to attack the carbonyl of the peptide bond. Zn2+ stabilises the transition state by interacting with the negative charged carbonyl oxygen atom of the tetrahedral intermediate.

Catalytic Residues Roles

UniProt PDB* (1lml)
His264, His268, His334 His264(165)A, His268(169)A, His334(235)A Forms part of the Zinc binding site. metal ligand
Glu265 Glu265(166)A It acts as a base to deprotonate a water molecule to allow its nucleophilic attack on the peptide bond. proton shuttle (general acid/base)
*PDB label guide - RESx(y)B(C) - RES: Residue Name; x: Residue ID in PDB file; y: Residue ID in PDB sequence if different from PDB file; B: PDB Chain; C: Biological Assembly Chain if different from PDB. If label is "Not Found" it means this residue is not found in the reference PDB.

Chemical Components

References

  1. Schlagenhauf E et al. (1998), Structure, 6, 1035-1046. The crystal structure of the Leishmania major surface proteinase leishmanolysin (gp63). DOI:10.1016/s0969-2126(98)00104-x. PMID:9739094.
  2. Macdonald MH et al. (1995), Biochim Biophys Acta, 1253, 199-207. Analysis of the active site and activation mechanism of the Leishmania surface metalloproteinase GP63. DOI:10.1016/0167-4838(95)00155-5. PMID:8519803.

Catalytic Residues Roles

Residue Roles
Glu265(166)A proton shuttle (general acid/base)
His264(165)A metal ligand
His268(169)A metal ligand
His334(235)A metal ligand

Chemical Components

Contributors

Mei Leung, Gemma L. Holliday, Charity Hornby