Extreme Engineering: Unlocking the Design Secrets of Deep-sea Microbes
The microbe Pyrodictium abyssi is an extremophile, thriving in the harsh conditions of deep-sea thermal vents. It can withstand temperatures above the boiling point of water, lacks light and oxygen, and endures immense pressure at ocean depths of thousands of meters. A recent study, published in Nature Communications, reveals the intricate design of its cannulae, tiny protein tubes that link cells together, and the simplicity of their construction method.
The research, led by scientists from Emory University, the University of Virginia, and Vrije Universiteit Brussel, showcases the cannulae's elegance and strength. Vincent Conticello, an Emory professor, describes the cannulae as resembling classical architecture columns, with fluted edges and precise regularity. The study demonstrates how calcium triggers protein molecules to self-assemble into cannulae structures, forming a stable microbial community.
This discovery has implications for biotechnology, inspiring innovations in 'smart' materials and nanoscale drug delivery systems. The research also sheds light on the possible role of cannulae as a transportation network for information and cargo, and suggests that Pyrodictium abyssi may provide insights into the emergence of multi-cellular life forms from the 'primal soup' of early Earth.
The study's co-first authors include Jessalyn Miller, Mike Steutel, and Ravi Sonani, with Emory graduate student Andres Gonzalez Socorro as a co-author. Co-senior authors are Han Remaut and Edward Egelman. The international collaboration involved researchers from the University of Lethbridge and the Max Plank Institute in Germany.
Archaea, a domain of microorganisms, were first discovered in Yellowstone National Park's hot springs in 1969. Since then, 'bio-prospectors' have found them in acidic deep mines, ice, and deep-sea vents. Some extremophiles belong to the Archaea domain, which is a new branch of life. Archaea thrive in extreme environments and are part of the microbiota of all organisms, including humans.
They were not properly classified until 1977 when genetic analysis revealed their distinct evolutionary lineage from bacteria and Eukarya. Pyrodictium abyssi, named for its Greek roots, was isolated from sea vents in 1991 by Karl Stetter. Scientists are investigating Archaea to identify enzymes that can function in extreme conditions, paving the way for bioengineered tools.
The Conticello lab focuses on developing proteins for biomedicine and complex technologies. Advances in cryogenic electron microscopy and AI technology have accelerated the study of protein structures. The AlphaFold AI system, developed by Google DeepMind, predicts protein structures with unprecedented accuracy and speed.
Conticello emphasizes the importance of understanding protein structure for function, citing Francis Crick's famous quote. The twisted structure of DNA determines its function, and protein structure is equally crucial. Studying Pyrodictium abyssi samples is challenging due to its high-pressure, oxygen-free environment and corrosive, toxic nature.
To study cannulae structure, the Conticello lab synthesizes the DNA sequence of the protein, implanting it into E. coli bacteria. They collaborate with the University of Virginia for detailed cryo-EM views and chemical analyses, demonstrating the domino effect of protein binding and the role of calcium ions.
The researchers submit synthesized cannulae structures to the Protein Data Bank, providing open access to accelerate scientific research. The study's findings have led to an international collaboration, showcasing the same architecture and molecular structure of lab-grown and cellular cannulae.
The authors further investigate the cannulae's potential as synthetic protein-based biomaterials, suggesting the possibility of transporting DNA. They have encased negatively charged gold nanoparticles in the cannulae, showcasing their biomedical applications.
The paper's support includes grants from the National Science Foundation, National Institutes of Health, Research Foundation-Flanders, and the Human Frontier Science Program.
