A recombinant heterotrimeric mini-procollagen I reveals new functional and structural roles for the α2(I) chain
Abstract
Collagen I provides mechanical stability to organs and plays a critical role in several physiological processes such as wound healing and bone remodeling. Its ability to form fibrils depends on the proteolytic conversion of soluble procollagen I into mature protomers. However, the mechanistic aspects of this critical step have been difficult to analyze due to the lack of recombinant procollagen I suitable for structural and biochemical analyses. Here, we describe the successful production and purification of a heterotrimeric mini-procollagen I [α1(I) 2 α2(I)] together with its homotrimeric counterpart [α1(I) 3 ] in HEK293-F cells. These tools were used to probe the specific role of the α2(I) chain both in procollagen I assembly and proteolytic maturation. While the presence of α2(I) in the heterotrimer does not strengthen trimer interfaces on its own, as revealed by cryo-electron microscopy, it provides a clear functional advantage to the procollagen substrate that is cleaved more efficiently by bone morphogenetic protein 1 (BMP-1) than the homotrimer. Furthermore, we demonstrate that the first cleavage event in the heterotrimer is at the level of the α2(I) chain, through a mechanism involving its C-telopeptide and a specific PRS motif close to the cleavage site. The preferential cleavage of α2(I) by BMP-1 can be partially corrected in the presence of PCPE-1 (procollagen C-proteinase enhancer 1) but the efficacy of the correction depends on its position on the procollagen trimer. Finally, we solved the high-resolution structure of the complex between the heterotrimer and PCPE-1 and proposed a new mechanism to explain the enhancing activity of PCPE-1.
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BibTeX
@misc{lipinski2026recombinant,
title = {{A recombinant heterotrimeric mini-procollagen I reveals new functional and structural roles for the α2(I) chain}},
author = {Oskar Lipiński and Cindy Dieryckx and Natacha Mariano and Priscillia Lagoutte and Hok Sau Kwong and Sandrine Vadon-Le Goff and Loïc Carrique and Catherine Moali},
howpublished = {HAL},
year = {2026},
month = oct,
doi = {10.64898/2026.10.03.756409},
url = {https://hal.science/hal-05782088v1},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - A recombinant heterotrimeric mini-procollagen I reveals new functional and structural roles for the α2(I) chain
AU - Oskar Lipiński
AU - Cindy Dieryckx
AU - Natacha Mariano
AU - Priscillia Lagoutte
AU - Hok Sau Kwong
AU - Sandrine Vadon-Le Goff
AU - Loïc Carrique
AU - Catherine Moali
PY - 2026
DA - 2026/10/03
PB - HAL
DO - 10.64898/2026.10.03.756409
UR - https://hal.science/hal-05782088v1
AB - Collagen I provides mechanical stability to organs and plays a critical role in several physiological processes such as wound healing and bone remodeling. Its ability to form fibrils depends on the proteolytic conversion of soluble procollagen I into mature protomers. However, the mechanistic aspects of this critical step have been difficult to analyze due to the lack of recombinant procollagen I suitable for structural and biochemical analyses. Here, we describe the successful production and purification of a heterotrimeric mini-procollagen I [α1(I) 2 α2(I)] together with its homotrimeric counterpart [α1(I) 3 ] in HEK293-F cells. These tools were used to probe the specific role of the α2(I) chain both in procollagen I assembly and proteolytic maturation. While the presence of α2(I) in the heterotrimer does not strengthen trimer interfaces on its own, as revealed by cryo-electron microscopy, it provides a clear functional advantage to the procollagen substrate that is cleaved more efficiently by bone morphogenetic protein 1 (BMP-1) than the homotrimer. Furthermore, we demonstrate that the first cleavage event in the heterotrimer is at the level of the α2(I) chain, through a mechanism involving its C-telopeptide and a specific PRS motif close to the cleavage site. The preferential cleavage of α2(I) by BMP-1 can be partially corrected in the presence of PCPE-1 (procollagen C-proteinase enhancer 1) but the efficacy of the correction depends on its position on the procollagen trimer. Finally, we solved the high-resolution structure of the complex between the heterotrimer and PCPE-1 and proposed a new mechanism to explain the enhancing activity of PCPE-1.
ER -