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PDBsum entry 3li7

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protein Protein-protein interface(s) links
Hydrolase inhibitor PDB id
3li7
Jmol
Contents
Protein chains
109 a.a. *
109 a.a. *
Waters ×133
* Residue conservation analysis
PDB id:
3li7
Name: Hydrolase inhibitor
Title: Crystal structure of sialostatin l
Structure: Putative secreted cystatin. Chain: a, b, c, d. Engineered: yes
Source: Ixodes scapularis. Blacklegged tick,shoulder tick. Organism_taxid: 6945. Expressed in: escherichia coli. Expression_system_taxid: 562.
Resolution:
2.67Å     R-factor:   0.241     R-free:   0.292
Authors: J.F.Andersen,M.Kotsyfakis,J.Salat,H.Horka
Key ref: M.Kotsyfakis et al. (2010). The crystal structures of two salivary cystatins from the tick Ixodes scapularis and the effect of these inhibitors on the establishment of Borrelia burgdorferi infection in a murine model. Mol Microbiol, 77, 456-470. PubMed id: 20545851
Date:
24-Jan-10     Release date:   29-Sep-10    
PROCHECK
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 Headers
 References

Protein chains
Pfam   ArchSchema ?
Q8MVB6  (Q8MVB6_IXOSC) -  Putative secreted cystatin
Seq:
Struc:
133 a.a.
109 a.a.
Protein chain
Pfam   ArchSchema ?
Q8MVB6  (Q8MVB6_IXOSC) -  Putative secreted cystatin
Seq:
Struc:
133 a.a.
109 a.a.
Key:    PfamA domain  Secondary structure  CATH domain

 Gene Ontology (GO) functional annotation 
  GO annot!
  Biochemical function     cysteine-type endopeptidase inhibitor activity     1 term  

 

 
Mol Microbiol 77:456-470 (2010)
PubMed id: 20545851  
 
 
The crystal structures of two salivary cystatins from the tick Ixodes scapularis and the effect of these inhibitors on the establishment of Borrelia burgdorferi infection in a murine model.
M.Kotsyfakis, H.Horka, J.Salat, J.F.Andersen.
 
  ABSTRACT  
 
Summary We have previously demonstrated that two salivary cysteine protease inhibitors from the Borrelia burgdorferi (Lyme disease) vector Ixodes scapularis -namely sialostatins L and L2- play an important role in tick biology, as demonstrated by the fact that silencing of both sialostatins in tandem results in severe feeding defects. Here we show that sialostatin L2 -but not sialostatin L- facilitates the growth of Borrelia burgdorferi in murine skin. To examine the structural basis underlying these differential effects of the two sialostatins, we have determined the crystal structures of both sialostatin L and L2. This is the first structural analysis of cystatins from an invertebrate source. Sialostatin L2 crystallizes as a monomer with an 'unusual' conformation of the N-terminus, while sialostatin L crystallizes as a domain-swapped dimer with an N-terminal conformation similar to other cystatins. Deletion of the 'unusual' N-terminal five residues of sialostatin L2 results in marked changes in its selectivity, suggesting that this region is a particularly important determinant of the biochemical activity of sialostatin L2. Collectively, our results reveal the structure of two tick salivary components that facilitate vector blood feeding and that one of them also supports pathogen transmission to the vertebrate host.