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Collagen's primary structure determines collagen:HSP47 complex stoichiometry

Abraham, Elena T. ; Oecal, Sinan ; Mörgelin, Matthias LU ; Schmid, Philipp W.N. ; Buchner, Johannes ; Baumann, Ulrich and Gebauer, Jan M. (2021) In Journal of Biological Chemistry 297(6).
Abstract

Collagens play important roles in development and homeostasis in most higher organisms. In order to function, collagens require the specific chaperone HSP47 for proper folding and secretion. HSP47 is known to bind to the collagen triple helix, but the exact positions and numbers of binding sites are not clear. Here, we employed a collagen II peptide library to characterize high-affinity binding sites for HSP47. We show that many previously predicted binding sites have very low affinities due to the presence of a negatively charged amino acid in the binding motif. In contrast, large hydrophobic amino acids such as phenylalanine at certain positions in the collagen sequence increase binding strength. For further characterization, we... (More)

Collagens play important roles in development and homeostasis in most higher organisms. In order to function, collagens require the specific chaperone HSP47 for proper folding and secretion. HSP47 is known to bind to the collagen triple helix, but the exact positions and numbers of binding sites are not clear. Here, we employed a collagen II peptide library to characterize high-affinity binding sites for HSP47. We show that many previously predicted binding sites have very low affinities due to the presence of a negatively charged amino acid in the binding motif. In contrast, large hydrophobic amino acids such as phenylalanine at certain positions in the collagen sequence increase binding strength. For further characterization, we determined two crystal structures of HSP47 bound to peptides containing phenylalanine or leucine. These structures deviate significantly from previously published ones in which different collagen sequences were used. They reveal local conformational rearrangements of HSP47 at the binding site to accommodate the large hydrophobic side chain from the middle strand of the collagen triple helix and, most surprisingly, possess an altered binding stoichiometry in the form of a 1:1 complex. This altered stoichiometry is explained by steric collisions with the second HSP47 molecule present in all structures determined thus far caused by the newly introduced large hydrophobic residue placed on the trailing strand. This exemplifies the importance of considering all three sites of homotrimeric collagen as independent interaction surfaces and may provide insight into the formation of higher oligomeric complexes at promiscuous collagen-binding sites.

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author
; ; ; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Journal of Biological Chemistry
volume
297
issue
6
article number
101169
publisher
American Society for Biochemistry and Molecular Biology
external identifiers
  • scopus:85120049047
  • pmid:34487762
ISSN
0021-9258
DOI
10.1016/j.jbc.2021.101169
language
English
LU publication?
yes
id
fd463d0c-8601-49d3-9889-436d181147b5
date added to LUP
2021-12-15 11:20:00
date last changed
2024-02-20 18:34:49
@article{fd463d0c-8601-49d3-9889-436d181147b5,
  abstract     = {{<p>Collagens play important roles in development and homeostasis in most higher organisms. In order to function, collagens require the specific chaperone HSP47 for proper folding and secretion. HSP47 is known to bind to the collagen triple helix, but the exact positions and numbers of binding sites are not clear. Here, we employed a collagen II peptide library to characterize high-affinity binding sites for HSP47. We show that many previously predicted binding sites have very low affinities due to the presence of a negatively charged amino acid in the binding motif. In contrast, large hydrophobic amino acids such as phenylalanine at certain positions in the collagen sequence increase binding strength. For further characterization, we determined two crystal structures of HSP47 bound to peptides containing phenylalanine or leucine. These structures deviate significantly from previously published ones in which different collagen sequences were used. They reveal local conformational rearrangements of HSP47 at the binding site to accommodate the large hydrophobic side chain from the middle strand of the collagen triple helix and, most surprisingly, possess an altered binding stoichiometry in the form of a 1:1 complex. This altered stoichiometry is explained by steric collisions with the second HSP47 molecule present in all structures determined thus far caused by the newly introduced large hydrophobic residue placed on the trailing strand. This exemplifies the importance of considering all three sites of homotrimeric collagen as independent interaction surfaces and may provide insight into the formation of higher oligomeric complexes at promiscuous collagen-binding sites.</p>}},
  author       = {{Abraham, Elena T. and Oecal, Sinan and Mörgelin, Matthias and Schmid, Philipp W.N. and Buchner, Johannes and Baumann, Ulrich and Gebauer, Jan M.}},
  issn         = {{0021-9258}},
  language     = {{eng}},
  number       = {{6}},
  publisher    = {{American Society for Biochemistry and Molecular Biology}},
  series       = {{Journal of Biological Chemistry}},
  title        = {{Collagen's primary structure determines collagen:HSP47 complex stoichiometry}},
  url          = {{http://dx.doi.org/10.1016/j.jbc.2021.101169}},
  doi          = {{10.1016/j.jbc.2021.101169}},
  volume       = {{297}},
  year         = {{2021}},
}