The bacteria on earth contain factories that are nanometer-sized, and they do numerous things. Some factories make nutrients while others make toxic materials that harms the bacteria. Researchers have no in-depth study about the functional diversity of these factories.
But all of the nanofactories have a common exterior, they all have a shell that is made of protein tiles. This inspired the researchers from Michigan State University to learn how to manipulate it in the lab. This will give them the opportunity to build nanofactories and use their own design and using the natural building blocks. The scientists see the structures of the nanofactories as the main source of new types of technology. Their main goal is to create and manipulate a nanofactory that will do things that they don't normally do in nature.
Cheryl Kerfeld's lab has reported in a new study that a new genetically engineered shell that is based on the natural structures and the natural principles of protein evolution was made. The shell is made of only a single designed protein, making it simpler. It is stated that it is easier to work with and has the chance to evolve in the lab. This study was published in ACS Synthetic Biology.
There are three types of proteins found in natural shells. The most common and abundant one is BMC-H. Around six BMC-H proteins come together to create a hexagon shape to tile the wall. In evolutionary history, some BMC-H protein pairs become joined together. These tandem, named BMC-T, merges to form a hexagon shape.
"The two halves of a BMC-T protein can evolve separately while staying next to each other, because they are fused together," said Bryan Ferlez, a postdoc in the Kerfeld lab. "This evolution allows for diversity in the structures and functions of BMC-T shell proteins, something that we want to recreate by design in the lab."
Taking an inspiration from the natural evolution, the researchers made an artificial BMC-T protein, named the BMC-H2, by merging two BMC-H protein. The new design that they made was deemed successful.
"To our surprise, BMC-H2 proteins form shells on their own," said. Sean McGuire a former undergraduate research student and technician in the Kerfeld lab. "They look like Wiffle balls, with gaps in the shell,"
The next experiment that they made was cover the gaps in the shell that look like a wiffle ball with BMC-P, which is the third type of protein in a shell that is said to form pentamers.
"The result is a shell, about 25 nanometers wide, made up of only two protein types: the new BMC-H2 and BMC-P," Bryan says. "It is around half the size of the structure built with all three protein types."
