Rqc2p protein "acts as an agent" to command the random assembly of amino acids

The first lesson you will learn in any introductory biology textbook is that our DNA spelled out the instructions to generate proteins Most of the work in our body cells is done by tiny machines like proteins The results of a study published in the January 2 issue of science defied science textbooks, confirming for the first time that amino acids, the building blocks of proteins, could be assembled without DNA and an intermediate template messenger RNA The team observed that another protein designated which amino acid to add Peter Shen, lead author of the paper and a postdoctoral researcher in biochemistry at the University of Utah, said: "this amazing finding reflects our incomplete understanding of biology Nature is much more capable than we realize " Treating cells as well run factories may help to understand the new findings Ribosomes are machines on protein assembly lines that connect amino acids together in the order specified by the genetic code When an error occurs, the ribosome may stop working and call quality control personnel to this site To clean up the mess, cells break down ribosomes, discard blueprints, and recycle some of the protein they produce And new research reveals an amazing role for rqc2p, a member of the quality control team that is conserved in a protein from yeast to humans Before the incomplete protein was recovered, rqc2p promoted the ribosome to add two kinds of amino acids: alanine and threonine in any order You can think of it as a car assembly line that continues to run without a command It picks up what can be picked up and randomly assembles: Horn wheel horn wheel wheel wheel wheel wheel wheel wheel wheel wheel wheel wheel wheel wheel horn "In this case, we have a protein that performs tasks normally performed by mRNA," said Dr Adam frost, an assistant professor at the University of California, San Francisco and an adjunct professor of Biochemistry at the University of Utah I like this story because it blurs the functional boundaries of what we used to think of as proteins " Forrest and Jonathan Weissman, Ph.D., researchers at the Howard Hughes Institute of medicine at the University of California, San Francisco, and onn brandman, Ph.D., of Stanford University, are co senior authors of the paper Just like installing extra horns and wheels on one side of a semi-finished car, proteins with an apparently random sequence of alanine and threonine look weird and may not work properly But this meaningless sequence may meet the special purpose The code could signal that the incomplete protein must be destroyed, or it could be part of a test to see if the ribosome is functioning properly There is evidence that there may be errors in one or both of the processes in some neurodegenerative diseases, such as Alzheimer's disease, amyotrophic lateral sclerosis (ALS) or Huntington's disease "There are many interesting potential situations in this work, and none of them can happen if we don't follow our curiosity," brandman said The main driver of discovery is to explore what you see, and that's what we do There will never be a substitute for it " When scientists see the evidence for themselves, they first consider that it is an unusual phenomenon They used a technique called a frozen electron microscope to freeze and then image the quality control machine in action "We captured rqc2p in action," Forrest said But this view is so far fetched It's our responsibility to prove it " They confirmed their hypothesis through extensive biochemical analysis The new RNA sequencing technology confirmed that rqc2p / ribosome complex may add some amino acids to the stopped proteins, because it also combines the tRNAs that bring the amino acids to the protein assembly line The specific tRNAs they saw carried only alanine and threonine Decisively, they determined that the stopped proteins were added to a wide range of alanine and threonine chains "Our job now is to determine when and where the process will take place and what will happen if it fails," Forrest said (source: Bio communication)