Periodic Reporting for period 1 - Collagen Origami (Collagen Origami)
Reporting period: 2020-09-01 to 2022-08-31
Collagen is the most abundant protein in mammals and the principal component of connective tissue. Mutations in collagen or its abnormal expression are associated with a number of diseases, e.g. the brittle bone disease or fibrosis. Collagen model peptides (CMPs) which mimic collagen’s intriguing triple-helical structure are used as synthetic surrogates to study this structural protein. In this project, we have shown that the functional groups at the ends of CMPs have a strong impact on the stability of collagen triple helices, a fact that has eluded the scientific community despite the more than 50-year history of CMPs.
We have synthesized a series of CMPs with systematically varied terminal functional groups. We used a combined experimental and computational approach to elucidate the origins of the observed effects of the terminal groups on the peptide self-assembly. Our results revealed that the end-groups affect the stability of collagen triple helices by an interplay of two main effects: 1) strand preorganization, i.e. the ability of the individual peptides to pre-form a structure that is suitable for interacting with the other two strands; and 2) interstrand H-bonding, i.e. strengthening the interactions that hold the three strands together. We also show that the contributions of the end-groups are additive and can be used to predict the stability of collagen triple helices.
The ability to rationally design CMPs with predictable properties is an indispensable tool for a multitude of applications. Our findings will guide the design of biological probes and drugs based on collagen hybridizing peptides as well as new synthetic collagen-based materials. Such probes and materials are being currently developed, e.g. as diagnostic tools to monitor tumor boundaries or treatments for chronic wounds. Our results will facilitate the design and implementation of these technologies.