Mechanical coupling is used to achieve modification and efficiency enhancement of protein drugs

Over the past few decades, protein drugs such as antibodies, enzymes and cytokines have developed rapidly and have become one of the most important categories in the
modern biopharmaceutical field.
Compared with small molecule drugs, protein drugs have the advantages
of high activity, strong specificity, low toxicity and clear biological function.
However, it also has inherently unstable and poor pharmacokinetics, often requiring modifications to improve its stability, enhance efficacy, and reduce side effects
.
At present, bioconjugation of protein drugs with various functional groups (such as polyethylene glycol or human serum albumin) has been shown to be an effective strategy to prolong the half-life of protein drugs in vivo, but shortcomings such as reduced biological activity, complex production process, and immunogenicity greatly limit the widespread application
of this method.
It is urgent to develop a new bioconjugation strategy to achieve protein drug modification and synergy
.

The mechanical coupling strategy effectively maintains the affinity and biological activity of protein primitives for the corresponding receptors, which can significantly improve the anti-heat aggregation ability of protein drugs, effectively prolong their in vivo half-life, and significantly enhance their tumor suppressor activity in vivo

Recently, based on its development, protein heterosol biosynthesis strategies (Angew.
Chem.
, Int.
Ed.
2020, 59, 16122), Professor Zhang Wenbin's research group in the School of Chemistry and Molecular Engineering used interferon (IFN, an antiviral and antitumor drug) as a model protein drug and albumin binding domain (ABD) as the model functional motif, and realized the mechanical coupling of IFN and ABD by rationally using the protein entanglement primitive p53dim and two mutually orthogonal fixed-point coupling strategies.
A novel protein heterosol hydrocarbon cat-IFN-ABD
was prepared.
It is worth noting that by replacing the homogeneous p53dim dimer that guides the entanglement of molecular chains with the heterodimer obtained by rational modification (J.
Am.
Chem.
Soc.
2021, 143, 18029), the synthesis yield and selectivity of isosolhydrocarbons have been greatly improved, providing a concise method
for the preparation of protein mechanical conjugates.

To further explore the structure-activity relationship of topologies, the researchers also constructed and synthesized linear and cyclic IFN-ABD fusion proteins (l/c-IFN-ABD) as control samples
together with wild-type interferons.
The results showed that cat-IFN-ABD not only completely retained the affinity of protein drugs and functional protein motifs to the corresponding receptors, but also had significantly improved resistance to heat aggregation
.
Since ABD can prolong the half-life of protein drugs in vivo by binding to human serum albumin, all IFN-ABD fusion proteins have a longer in vivo half-life than wild-type interferon, especially cat-IFN-ABD, up to 11.
8 hours
.
Bioimaging further showed that cat-IFN-ABD had the most pronounced enrichment
at the tumor site compared to other samples.
Therefore, cat-IFN-ABD ultimately showed the best antitumor activity in mouse tumor models, highlighting the functional advantages of
mechanical coupling.
This work expands the linear backbone of proteins into a chain link structure, which can significantly improve the stability and efficacy
of fusion protein drugs while realizing functional integration.
Since this method is also compatible with other existing biological modification technologies, it has great application potential
in the development of a new generation of protein drugs.

The study was recently published online in J.
Am.
Chem.
Soc.
(https://pubs.
acs.
org/doi/full/10.
1021/jacs.
2c06532) and was soon recommended and reviewed by Faculty Opinions (https://facultyopinions.
com/article/742344893).

Liu Yajie, a postdoctoral fellow at the School of Chemistry and Molecular Engineering of Peking University, is the first author
of the paper.
Zhang Wenbin and Wei Wei, a researcher at the Institute of Process Engineering, Chinese Academy of Sciences, are the corresponding authors
of the paper.
This work was supported
by the National Natural Science Foundation of China, the National Key Research and Development Program of the Ministry of Science and Technology, the Beijing National Research Center for Molecular Sciences, the Clinical Medicine + X Youth Special Program of Peking University, the State Key Laboratory of Biochemical Engineering Open Fund, and the China Postdoctoral Science Foundation.