The Thermal Stability of the Collagen Triple Helix Is Tuned According to the Environmental Temperature.

Triple helix formation of procollagen occurs in the endoplasmic reticulum (ER) where the single-stranded α-chains of procollagen undergo extensive post-translational modifications. The modifications include prolyl 4- and 3-hydroxylations, lysyl hydroxylation, and following glycosylations. The modifications, especially prolyl 4-hydroxylation, enhance the thermal stability of the procollagen triple helix.

Lowering the culture temperature corrects collagen abnormalities caused by HSP47 gene knockout.

Heat shock protein 47 (HSP47) is an endoplasmic reticulum (ER)-resident molecular chaperone that specifically recognizes triple helical portions of procollagens. The chaperone function of HSP47 is indispensable in mammals, and hsp47-null mice show an embryonic lethal phenotype accompanied by severe abnormalities in collagen-based tissue structures. Two leading hypotheses are currently accepted for the molecular function of HSP47 as a procollagen-specific chaperone.

Structural optimization of cyclic peptides that efficiently detect denatured collagen.

To develop a facile method for detecting denatured collagen, we investigated the structure-activity relationship of cyclic collagen-mimetic peptides (cCMPs). Reported cCMP prototypes tend to self-assemble and they must be disassembled just before use. Introducing charge repulsion and a deformation in the peptide backbone structure enabled cCMPs to detect denatured collagen without a pre-treatment for disassembly.

Cyclic Peptides for Efficient Detection of Collagen.

We report here a new class of collagen-binding peptides, cyclic collagen-mimetic peptides (cCMPs), that efficiently hybridize with the triple-helix-forming portions of collagen. cCMPs are composed of two parallel collagen-like (Xaa-Yaa-Gly) strands with both termini tethered by covalent linkages. Enzyme-linked immunosorbent assays and western blotting analysis showed that cCMPs exhibit more potent affinity toward collagen than reported collagen-binding peptides and can specifically detect different collagen polypeptides in a mixture of proteins.