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Structure of native protein C inhibitor provides insight into its multiple functions

Liu, Wei; Adams, Ty E.; Kjellberg, Margareta LU ; Stenflo, Johan LU and Huntington, James A (2007) In Journal of Biological Chemistry 282(18). p.13759-13768
Abstract
Protein C inhibitor (PCI) is a multifunctional serpin with wide ranging protease inhibitory functions, unique cofactor binding activities, and potential non-inhibitory functions akin to the hormone-transporting serpins. To gain insight into the molecular mechanisms utilized by PCI we developed a robust expression system in Escherichia coli and solved the crystal structure of PCI in its native state. The five monomers obtained from our two crystal forms provide an NMR-like ensemble revealing regions of inherent flexibility. The reactive center loop (RCL) of PCI is long and highly flexible with no evidence of hinge region incorporation into beta-sheet A, as seen for other heparin-binding serpins. We adapted an extrinsic fluorescence method... (More)
Protein C inhibitor (PCI) is a multifunctional serpin with wide ranging protease inhibitory functions, unique cofactor binding activities, and potential non-inhibitory functions akin to the hormone-transporting serpins. To gain insight into the molecular mechanisms utilized by PCI we developed a robust expression system in Escherichia coli and solved the crystal structure of PCI in its native state. The five monomers obtained from our two crystal forms provide an NMR-like ensemble revealing regions of inherent flexibility. The reactive center loop (RCL) of PCI is long and highly flexible with no evidence of hinge region incorporation into beta-sheet A, as seen for other heparin-binding serpins. We adapted an extrinsic fluorescence method for determining dissociation constants for heparin and find that the N-terminal tail of PCI and residues adjacent to helix H are not involved in heparin binding. The minimal heparin length capable of tight binding to PCI was determined to be chains of eight monosaccharide units. A large hydrophobic pocket occupied by hydrophobic crystal contacts was found in an analogous position to the hormone-binding site in thyroxine-binding globulin. In conclusion, the data presented here provide important insights into the mechanisms by which PCI exercises its multiple inhibitory and non-inhibitory functions. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Journal of Biological Chemistry
volume
282
issue
18
pages
13759 - 13768
publisher
ASBMB
external identifiers
  • wos:000246060300066
  • scopus:34250332236
ISSN
1083-351X
DOI
10.1074/jbc.M701074200
language
English
LU publication?
yes
id
1b430420-f4da-45e6-b477-15a350c607f2 (old id 663053)
date added to LUP
2007-12-14 14:29:01
date last changed
2017-11-19 03:38:20
@article{1b430420-f4da-45e6-b477-15a350c607f2,
  abstract     = {Protein C inhibitor (PCI) is a multifunctional serpin with wide ranging protease inhibitory functions, unique cofactor binding activities, and potential non-inhibitory functions akin to the hormone-transporting serpins. To gain insight into the molecular mechanisms utilized by PCI we developed a robust expression system in Escherichia coli and solved the crystal structure of PCI in its native state. The five monomers obtained from our two crystal forms provide an NMR-like ensemble revealing regions of inherent flexibility. The reactive center loop (RCL) of PCI is long and highly flexible with no evidence of hinge region incorporation into beta-sheet A, as seen for other heparin-binding serpins. We adapted an extrinsic fluorescence method for determining dissociation constants for heparin and find that the N-terminal tail of PCI and residues adjacent to helix H are not involved in heparin binding. The minimal heparin length capable of tight binding to PCI was determined to be chains of eight monosaccharide units. A large hydrophobic pocket occupied by hydrophobic crystal contacts was found in an analogous position to the hormone-binding site in thyroxine-binding globulin. In conclusion, the data presented here provide important insights into the mechanisms by which PCI exercises its multiple inhibitory and non-inhibitory functions.},
  author       = {Liu, Wei and Adams, Ty E. and Kjellberg, Margareta and Stenflo, Johan and Huntington, James A},
  issn         = {1083-351X},
  language     = {eng},
  number       = {18},
  pages        = {13759--13768},
  publisher    = {ASBMB},
  series       = {Journal of Biological Chemistry},
  title        = {Structure of native protein C inhibitor provides insight into its multiple functions},
  url          = {http://dx.doi.org/10.1074/jbc.M701074200},
  volume       = {282},
  year         = {2007},
}