Fluorescent Biosensor Aidding Drug Development created

Researchers at Carnegie Mellon University have developed a new fluorescent biosensor that could aid in the development of an important class of drugs that target a crucial class of proteins called G protein-coupled receptors (GPCRs).

"Drugs that target GPCRs make up approximately 30 percent of all pharmaceuticals currently on the market, including some of the most prescribed drugs," said Jonathan Jarvik, the Carnegie Mellon Biological Sciences professor who led the effort to develop the GPCR biosensor. "This prevalence makes assays for the receptors a billion dollar industry."

GPCRs are popular drug targets because of the pivotal role they play in cells' chemical communication circuits that are responsible for regulating functions critical to health, including circuits involved in heart and lung function, mood, cognition and memory, digestion and the inflammatory response. Found in the cell membrane, GPCRs interact with molecules responsible for cellular communication such as neurotransmitters and hormones. When one of the receptors encounters such a molecule, it relays a signal across the cell membrane that, in turn, initiates a response. After the response is triggered, the receptor retreats from the membrane into the cell's interior.

To create the GPCR biosensor, the research team used a new technology called fluoromodules. Invented by Carnegie Mellon's Molecular and Biosensor Imaging Center (MBIC), fluoromodules are probes that allow scientists to monitor the activities of individual proteins found in living cells in real-time. The probes are made up of two components: a fluorogen-activating protein (FAP) and a non-fluorescent dye called a fluorogen. The FAP is attached to the protein that is being studied, and the fluorogen is engineered to bind to the FAP. When the two meet, they cast off a glow that can be detected using a variety of methods, alerting researchers to the protein's location and activity. The FAP's fluorescence can be turned on and off by adding or removing the fluorogen, a characteristic that makes the fluoromodules more useful than other fluorescent proteins.

In the current study, which is published in the July issue of the Journal of Biomolecular Screening, Jarvik and colleagues engineered a fluoromodule that would readily determine when GPCR retreats from the cell membrane. The researchers genetically expressed a FAP fused to the beta2 adrenergic receptor (b2AR), a well-studied GPCR that is present in brain, heart, lung and other tissues. When the researchers introduced its associated membrane-impermeant fluorogen, it bound to the FAP-tagged GPCR on the cell surface, emitting a bright fluorescent glow. When the receptor was activated and had retreated into the cell, the fluorescence dimmed.

The new biosensor is notable, Jarvik said, because it looks directly at the receptor and provides what is known as a homogeneous, or mix-and-read, assay that can be scaled to screen large numbers of molecules to identify new drug leads. 

The researchers are hopeful that this technology can be generalized across other receptors and cell-surface proteins, and are currently researching its broader applications.

This research was funded by the National Institutes of Health (NIH). MBIC is one of the NIH's National Technology Centers for Networks and Pathways. For more information, visit: http://www.mbic.cmu.edu/.


sciencedaily

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Scientists Create Super-Strong Collagen

Collagen is the most abundant protein in the human body — the structural scaffold that holds together bones, tendons, skin, and connective tissue. Its remarkable strength and flexibility come from a distinctive triple-helix molecular structure, where three protein chains wind tightly around each other like a rope. Scientists have long been fascinated by the collagen helix, both as a window into fundamental biology and as a template for designing stronger biomaterials. A new study has pushed that understanding further, engineering an especially stable version of the collagen triple helix.

Published in the Proceedings of the National Academy of Sciences, the research describes how scientists were able to enhance collagen's structural stability through careful modifications to the amino acid sequence that forms the helix. Collagen triple helices depend heavily on a specific amino acid pattern, with proline and hydroxyproline playing key roles. By understanding and precisely manipulating the interactions between these amino acids, the team was able to create collagen-mimicking peptides that form extraordinarily stable triple helices — more thermally stable than natural collagen.

Why Stability Matters

Thermal stability in a protein is often a proxy for structural robustness more generally. A collagen helix that unwinds at higher temperatures is better able to maintain its structure under physiological stress, making it more suitable for medical applications like tissue engineering scaffolds, wound healing matrices, and drug delivery systems that need to survive in the body for extended periods.

Beyond medicine, super-strong collagen analogs could find uses in high-performance materials science. Collagen-inspired fibers and composites could potentially offer the combination of strength, flexibility, and biocompatibility that synthetic polymers struggle to match.

Broader Implications

Understanding what makes collagen so structurally resilient at the molecular level also sheds light on diseases where collagen is disrupted — conditions like osteogenesis imperfecta (brittle bone disease) and various connective tissue disorders. Engineering better collagen analogs is not just a materials science achievement; it's a step toward treatments for these conditions and toward understanding the structural biology of one of life's most essential proteins.

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Source: Proceedings of the National Academy of Sciences

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World's first living synthetic cell created!!!!

A team led by rockstar Biologist Craig Venter has become the first in human history to synthesise a living cell completely from scratch. The achievement comes at the end of 10 years of research by 20 scientists, and at a cost of around $40 million (£27.7 million).

The microbe hasn't yet been officially named, but it may end up being called Mycoplasma laboratorium, referencing its origins. The goal behind the research is to be able to produce bacteria and microbes on-demand that can be used as biofuels, break down oil slicks, eat up carbon dioxide from the atmosphere, and even create vaccines fortreating diseases. This is the first step in that process, however, which just consisted of the creation of a near-clone of another bacterium.

Previously, the scientists had managed to create a synthetic genome, and had been able to transplant one bacteria's genome into another, but this is the first time that the two processes have been combined for the creation of a cell with an entirely synthetic genome inside. The cell reproduced over a billion times, making copies that were controlled by the synthetic DNA. It's the first time that synthetic DNA has been in complete control of a cell.

The research was reported in the journal Science, which Venter told: "This is an important step both scientifically and philosophically, it has certainly changed my views of definitions of life and how life works." However, some have raised concern that synthetic organisms could escape and cause unforeseen environmental problems, or be reverse-engineered into a chemical weapon. Religious groups complained that Venter was playing god.

Venter says that's not the case: "That's a term that comes up every time there's a new medical or scientific breakthrough associated with biology. It's been a goal of humanity from the earliest ages to try and control nature -- that's how we got agriculture, that's how we got domesticated animals. This is the next stage in our understanding of how life fundamentally works."

He added: "There is a slight increase in the potential for harm, but there is an exponential increase in the potential benefit to society."

The organism has watermarks written into its DNA that will be able to identify it as synthetic if it escapes the lab and starts breeding in the wild. 

The next step for Venter and his team is to break down the organism, taking out different parts to establish what the minimum number of genes is for life to exist. From there, more specialised cells could be created and the simpler the creation, the less risk there is of unintended consequences. That's a situation that nobody -- particularly Venter -- wants to happen.

www.wired.co.uk   

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