In The Rational Essence of Proteins and DNA Mike Gene discusses how perfectly the shape of amino acids (the building blocks of proteins) and nucleotides (the building blocks of DNA and RNA) seem to be made for each other.
According to Thomist philosopher Edward Feser, Thomists reject the idea that living organisms are machines, since "the parts of an artifact have no inherent tendency to come together and function as a coffee machine, or computer, or whatever, but have to be arranged by us to do so," whereas (apparently) the parts of living organisms do have an inherent tendency to come together and function.
I've suggested that Feser's view of living organisms is incorrect. Scientists have been trying to find a way that parts of living organisms could come together, without anybody arranging them, with no success. In fact, it's difficult to even come up with some of the key parts, such as nucleotides, without a lot of intervention by somebody.
But perhaps Mike Gene's essay offers us a way of harmonizing Thomist philosophy with what appears to be the data. God has indeed created the parts of living organisms so that once they are brought together in the proper way, they will indeed become living organisms. They may resemble the kinds of machines that we humans make, but they are God's machines, where the parts were created for each other. A match made in Heaven.