A protein from cyanobacteria has been redesigned into a homing beacon to attract molecular payloads. The long-term goal: to organize resources inside living cells for medical or industrial applications.
'Hoarding' resources in the same location encourages more efficient chemical reactions. Someday, we could use this system to enhance the production of rubber, biofuels, and other commodities.
The genetically engineered shell is based on natural structures and the principles of protein evolution. Scientists see such structures as a source of new industrial or medical technologies.
MSU scientists report how cyanobacteria line up their CO2-fixing factories within them in a system that works like Velcro. The research is part of an effort to control and repurpose these factories to make products for human consumption.
The new methods let scientists assemble the factories on demand and insert custom molecules inside them for further processing. The aim is to eventually design sustainable medical, industrial, or energy applications.
The Kerfeld lab announces two new methods for manipulating bacterial factories for biotech aims: one is to screen and extract the factories, the other is to predictably insert custom enzymes in them.
A peek into the logistics of how bacterial nanofactories move electrons, towards creating chemical products. Future apps include renewable energy and medical tools.
Scientists are learning how bacterial nanofactories are constructed in nature. Recent experiments show we could engineer their building blocks into new structures, for useful applications.
The Kerfeld lab has analyzed over 200 sets of cyanobacteria DNA. This knowledge is getting us closer to understanding how to build synthetic factories that will someday produce green fuels or products used to diagnose diseases.
Unpacking a new bacterial mini-factory
Many bacteria contain microcompartments that function like mini-factories, efficiently processing compounds for diverse purposes. For example, they sequester toxic intermediates in organisms like the notorious Salmonella and Escherichia; or in cyanobacteria, they enhance the efficiency of photosynthesis.
The PRL’s Kerfeld lab is at the forefront of understanding different kinds of these bacterial microcompartments - how they work and are built - with the goal of bioengineering them someday to produce sustainable energy sources and other “green” or medical products, without using fossil fuels.
And in a recent publication in Scientific Reports, Dr. Jan Zarzycki, a former post-doc in the Kerfeld lab, describes a new microcompartment widely spread among different kinds of bacteria, increasing our understanding of the enzymes packed within it.
Bacterial starter kits
Although many bacterial microcompartments share a common way of processing compounds into useful products, they differ in what compounds they employ as raw materials.
“These compartments’ functions are defined by what enzymes they package,” says Jan, currently a post-doc with Dr. Tobias Erb at the Max Planck Institute for Terrestrial Microbiology. “Specifically, the enzyme that catalyzes the very first step of the reaction sequence determines the overall function.”
The defining enzyme in Jan’s newly described microcompartment is a so-called glycyl radical enzyme (GRE).
“GREs that are not associated with microcompartments have been widely studied. However, now, in the era of genome sequencing, tons of GRE encoding genes are popping up in databases, many accompanied by bacterial microcompartment genes. These GREs appear to have novel functions inside the mini-factories, and some functions have been recently described.”
Jan adds that although these functions can sometimes be predicted with bioinformatics methods, the challenge is to demonstrate them in the lab.
“Unfortunately, GREs are hard to directly examine, because they are destroyed after the slightest contact with oxygen. It took us a lot of effort to work with a GRE under strictly oxygen-free conditions, but we were able to determine and prove its function, and thus the function of the microcompartment it is involved with.”
From biology to engineering applications
Synthetic biologists are very interested in the versatility of the GREs and their microcompartments, as they could become a platform for designing molecular pathways that sustainably produce “green” chemicals, medicines, renewable materials like rubber, even renewable energy.
“In the big picture, in order to transform biology to become a real engineering science, we first need to understand how nature, and in this case, microcompartments work. This knowledge would enable us to potentially reassemble those mini-factories to perform these new functions in both bacteria and plants.”
“Biologists can already engineer single enzymes that work as well, if not better, than natural ones. But building complex systems with multiple enzymes is still a great challenge, because we often don’t understand the natural systems well enough.”
The protein, peroxiredoxin Q, is known to maintain a healthy balance of chemicals and energy levels in chloroplasts. The new research shows the protein also impacts the system that produces chloroplast membranes.
The CAMTA system - which is known to protect plants from cold weather - plays a newly discovered role: when bacteria invade a leaf, CAMTA warns neighboring, unaffected leaves to prepare for invasion.
When algae get stressed, they hibernate and store energy in forms that we can use to make biofuels. Understanding how stress impacts algal hibernation could help scientists lower the cost of biofuels production.