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Displacement of the occluding loop by the parasite protein, chagasin, results in efficient inhibition of human cathepsin

Redzynia, Izabela; Ljunggren, Anna LU ; Abrahamson, Magnus LU ; Mort, John S.; Krupa, Joanne C.; Jaskolski, Mariusz and Bujacz, Grzegorz (2008) In Journal of Biological Chemistry 283(33). p.22815-22825
Abstract
Cathepsin B is a papain-like cysteine protease showing both endo- and exopeptidase activity, the latter due to a unique occluding loop that restricts access to the active site cleft. To clarify the mode by which natural protein inhibitors manage to overcome this obstacle, we have analyzed the structure and function of cathepsin B in complexes with the Trypanosoma cruzi inhibitor, chagasin. Kinetic analysis revealed that substitution of His-110e, which anchors the loop in occluding position, results in 3-fold increased chagasin affinity (K-i for H110A cathepsin B, 0.35 nM) due to an improved association rate (kon, 5 x 105 M(-1)s(-1)). The structure of chagasin in complex with cathepsin B was solved in two crystal forms (1.8 and 2.67 A... (More)
Cathepsin B is a papain-like cysteine protease showing both endo- and exopeptidase activity, the latter due to a unique occluding loop that restricts access to the active site cleft. To clarify the mode by which natural protein inhibitors manage to overcome this obstacle, we have analyzed the structure and function of cathepsin B in complexes with the Trypanosoma cruzi inhibitor, chagasin. Kinetic analysis revealed that substitution of His-110e, which anchors the loop in occluding position, results in 3-fold increased chagasin affinity (K-i for H110A cathepsin B, 0.35 nM) due to an improved association rate (kon, 5 x 105 M(-1)s(-1)). The structure of chagasin in complex with cathepsin B was solved in two crystal forms (1.8 and 2.67 A resolution), demonstrating that the occluding loop is displaced to allow chagasin binding with its three loops, L4, L2, and L6, spanning the entire active site cleft. The occluding loop is differently displaced in the two structures, indicating a large range of movement and adoption of conformations forced by the inhibitor. The area of contact is slightly larger than in chagasin complexes with the endopeptidase, cathepsin L. However, residues important for high affinity to both enzymes are mainly found in the outer loops L4 and L6 of chagasin. The chagasin- cathepsin B complex provides a structural framework for modeling and design of inhibitors for cruzipain, the parasite cysteine protease and a virulence factor in Chagas disease. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Journal of Biological Chemistry
volume
283
issue
33
pages
22815 - 22825
publisher
ASBMB
external identifiers
  • wos:000258321000049
  • scopus:53049095258
ISSN
1083-351X
DOI
10.1074/jbc.M802064200
language
English
LU publication?
yes
id
31a91d7e-3f63-421d-b28a-3b61ff058d6a (old id 1253387)
date added to LUP
2008-10-30 12:25:52
date last changed
2017-11-19 03:35:30
@article{31a91d7e-3f63-421d-b28a-3b61ff058d6a,
  abstract     = {Cathepsin B is a papain-like cysteine protease showing both endo- and exopeptidase activity, the latter due to a unique occluding loop that restricts access to the active site cleft. To clarify the mode by which natural protein inhibitors manage to overcome this obstacle, we have analyzed the structure and function of cathepsin B in complexes with the Trypanosoma cruzi inhibitor, chagasin. Kinetic analysis revealed that substitution of His-110e, which anchors the loop in occluding position, results in 3-fold increased chagasin affinity (K-i for H110A cathepsin B, 0.35 nM) due to an improved association rate (kon, 5 x 105 M(-1)s(-1)). The structure of chagasin in complex with cathepsin B was solved in two crystal forms (1.8 and 2.67 A resolution), demonstrating that the occluding loop is displaced to allow chagasin binding with its three loops, L4, L2, and L6, spanning the entire active site cleft. The occluding loop is differently displaced in the two structures, indicating a large range of movement and adoption of conformations forced by the inhibitor. The area of contact is slightly larger than in chagasin complexes with the endopeptidase, cathepsin L. However, residues important for high affinity to both enzymes are mainly found in the outer loops L4 and L6 of chagasin. The chagasin- cathepsin B complex provides a structural framework for modeling and design of inhibitors for cruzipain, the parasite cysteine protease and a virulence factor in Chagas disease.},
  author       = {Redzynia, Izabela and Ljunggren, Anna and Abrahamson, Magnus and Mort, John S. and Krupa, Joanne C. and Jaskolski, Mariusz and Bujacz, Grzegorz},
  issn         = {1083-351X},
  language     = {eng},
  number       = {33},
  pages        = {22815--22825},
  publisher    = {ASBMB},
  series       = {Journal of Biological Chemistry},
  title        = {Displacement of the occluding loop by the parasite protein, chagasin, results in efficient inhibition of human cathepsin},
  url          = {http://dx.doi.org/10.1074/jbc.M802064200},
  volume       = {283},
  year         = {2008},
}