Abstract
Alpha-helical coiled-coils are widely occurring protein oligomerization motifs. Here we show that most members of the collagen superfamily contain short, repeating heptad sequences typical of coiled coils. Such sequences are found at the N-terminal ends of the C-propeptide domains in all fibrillar procollagens. When fused C-terminal to a reporter molecule containing a collagen-like sequence that does not spontaneously trimerize, the C-propeptide heptad repeats induced trimerization. C-terminal heptad repeats were also found in the oligomerization domains of the multiplexins (collagens XV and XVIII). N-terminal heptad repeats are known to drive trimerization in transmembrane collagens, whereas fibril-associated collagens with interrupted triple helices, as well as collagens VII, XIII, XXIII, and XXV, were found to contain heptad repeats between collagen domains. Finally, heptad repeats were found in the von Willebrand factor A domains known to be involved in trimerization of collagen VI, as well as in collagen VII. These observations suggest that coiled-coil oligomerization domains are widely used in the assembly of collagens and collagen-like proteins.
Highlights
The mechanisms controlling chain oligomerization in extracellular matrix and related proteins are currently topics of active research [1, 2]
The extent of the heptad repeat pattern is similar to that found in the collectins (Fig. 1B), again C-terminal to the collagenous region
Putative coiled-coil regions were found C-terminal to the triple helix in the fibrillar procollagens XXIV [42] and XXVII [43, 44] (Fig. 1A)
Summary
The mechanisms controlling chain oligomerization in extracellular matrix and related proteins are currently topics of active research [1, 2]. Studies on the procollagen precursors of the fibrillar collagens (types I–III, V, and XI) [6] showed that the C-propeptide regions are necessary to direct correct chain association, which is followed by zipper-like folding of the triple helix in the C- to N-terminal direction [7]. This concept was subsequently extended to basement membrane collagen type IV (8 –10), microfibril-forming collagen VI [11, 12], members of the C1q family [13] including collagens VIII and X (14 –17) and the emilins [18], and the FACITs1 (19 –21). With interrupted triple helices; CHO, Chinese hamster ovary; CPII, C-propeptide region of procollagen II; CRD, carbohydrate recognition domain; SP-D, surfactant protein-D; BS3, bis-(sulfosuccinimidyl)suberate; MBP, mannan-binding protein; TFE, trifluoroethanol
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
