Original source: Materials Today
The field of materials science has become abuzz with metal-organic frameworks (MOFs), versatile compounds made up of metal ions connected to organic ligands that can form one-, two-, or three-dimensional structures. There is an ever-growing list of applications for MOFs, including separating petrochemicals, storing hydrogen, and detoxing water from heavy metals and fluoride anions.
Recently, scientists have also begun making MOFs from building blocks that typically make up biomolecules, e.g. amino acids for proteins or nucleic acids for DNA. Like traditional MOFs, these biologically derived MOFs could find use in chemical catalysis, but can also be used as models for complex biomolecules that are difficult to isolate and study with other means.
Now, a team of chemical engineers at Ecole Polytechnique Fédérale de Lausanne (EPFL) Valais Wallis in Switzerland have synthesized a new biologically-derived MOF called SION-19 that can be used as a ‘nanoreactor’ – a place where tiny, otherwise-inaccessible reactions can take place. Led by Kyriakos Stylianou, scientists from the labs of Berend Smit and Lyndon Emsley constructed the new MOF with adenine molecules – one of the four nucleobases that make up DNA and RNA.
They did this to mimic the functions of DNA, which include hydrogen-bonding interactions between adenine and another nucleobase, thymine. This is a critical step in the formation of the DNA double helix, but also contributes to the overall folding of DNA and RNA inside the cell.
Studying their new MOF, the researchers found that thymine molecules can diffuse within its pores. Simulating this diffusion, they discovered that thymine molecules become hydrogen-bonded to adenine molecules inside the MOF’s cavities, mimicking what happens with DNA. They report these findings in a paper in Nature Communications.
“The adenine molecules act as structure-directing agents and ‘lock’ thymine molecules in specific positions within the cavities of our MOF,” says Stylianou. The researchers were able to take advantage of this locking by illuminating the thymine-loaded MOF, as a way to catalyze a chemical reaction.
This caused the thymine molecules to be dimerized into a di-thymine product, which the scientists were able to be isolate – a huge advantage given that di-thymine is related to skin cancer and can now be easily isolated and studied.
“Overall, our study highlights the utility of biologically derived MOFs as nanoreactors for capturing biological molecules through specific interactions, and for transforming them into other molecules,” says Stylianou.