Posts Tagged ‘protein’

Cockroach milk

Posted: July 28, 2016 in food
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The sight of cockroaches may evoke disgust but they can be a boon for human health, said a team of scientists who have shown that milk protein crystals found in roaches can serve as a “fantastic” protein supplement.

The team of scientists, including those from the Institute for Stem Cell Biology and Regenerative Medicine (inStem) in Bengaluru, has recently unravelled the structure of milk proteins crystals in the guts of a roach species called Diploptera punctata, the only known viviparous cockroach (which gives birth to live young).

A single crystal is estimated to contain more than three times the energy of an equivalent mass of dairy (buffalo) milk, according to the study by inStem’s Ramaswamy group.

“The crystals are like a complete food — they have proteins, fats and sugars. If you look into the protein sequences, they have all the essential amino acids,” said Sanchari Banerjee, one of the main authors of the paper published in July in the journal from the International Union of Crystallography.

Now, armed with the gene sequences for these milk proteins, Ramaswamy and colleagues plan to use a yeast system to produce these crystals en masse.

“They’re very stable. They can be a fantastic protein supplement,” said Ramaswamy.

Furthermore, their crystalline nature offers a unique advantage. As the protein in the solution is used up, by being digested, the crystal releases protein at an equivalent rate.

“It’s time-released food,” explained Ramaswamy, adding “if you need food that is calorifically high, that is time released and food that is complete. This is it”.

Besides their utility as supplemental food, the scaffolding in the protein crystals exhibit characteristics that could be used to design nanoparticles for drug delivery.

The other scientists involved are affiliated to National Centre for Advancing Translational Sciences, National Institutes of Health in the US, Structural Biology Research Centre, High Energy Accelerator Research Organisation in Japan, Centre for Cellular and Molecular Platforms (C-CAMP) in India, Department of Cell and Systems Biology, University of Toronto in Canada, University of Iowa in the US and Experimental Division, Synchrotron SOLEIL in France.


In our cells, proteins are the tiny machines that do most of the work. And the instructions for making proteins — and for piecing together their building blocks, called amino acids — are laid out by DNA, then relayed through RNA. But now, researchers show for the first time that amino acids can be assembled by another protein — without genetic instructions. These surprising findings were published in Science this week.

If a cell is an automobile-making factory, then ribosomes are the machines on the protein assembly line that links together amino acids in an order specified by DNA and messenger RNA (mRNA), an intermediate template. If something goes awry and a ribosome stalls, the quality control team shows up to disassemble the ribosome, discard that bit of genetic blueprint, and recycle the partially-made protein.

Turns out, that assembly line can keep going even if it loses its genetic instructions, according to a large U.S. team led by University of Utah, University of California, San Francisco, and Stanford researchers. They discovered an unexpected mechanism of protein synthesis where a protein, and not the normal genetic blueprint, specifies which amino acids are added.

“In this case, we have a protein playing a role normally filled by mRNA,” UCSF’s Adam Frost says in a news release. “I love this story because it blurs the lines of what we thought proteins could do.”

Frost and colleagues found a never-before-seen role for one member of the quality control team: a protein named Rqc2, which helps recruit transfer RNA (tRNA) to sites of ribosomal breakdowns (tRNA is responsible for bringing amino acids to the protein assembly line). Before the incomplete protein gets recycled, Rqc2 prompts the stalled ribosomes to add two amino acids — alanine and threonine — over and over. And that’s because the Rqc2–ribosome complex binds tRNAs that carry those two specific amino acids. In the auto analogy, the assembly line keeps going despite having lost its instructions, picking up whatever it can and attaching it in no particular order: horn-wheel-wheel-horn-wheel-wheel-wheel-wheel-horn, for example.

Pictured above, Rqc2 (yellow) binds tRNAs (blue and teal), which add amino acids (bright sot in the middle) to a partially-made protein (green). The complex binds the ribosome (white). A truncated protein with a seemingly random sequence of alanines and threonines probably doesn’t work properly, and that tail could be a code that signals for the malformed protein to be destroyed.

Thanks to Kebmodee for bringing this to the attention of the It’s Interesting community.