Open any introductory biology textbook and one of the first things you’ll learn is that our DNA spells out the instructions for making proteins, tiny machines that do much of the work in our body’s cells. Results from a study published on Jan. 2 in Science defy textbook science, showing for the first time that the building blocks of a protein, called amino acids, can be assembled without blueprints – DNA and an intermediate template called messenger RNA (mRNA). A team of researchers has observed a case in which another protein specifies which amino acids are added.
A new finding goes against dogma, showing for the first time that the building blocks of a protein, called amino acids, can be assembled by another protein, and without genetic instructions). The Rqc2 protein (yellow) binds tRNAs (dark blue, teal) which add amino acids (bright spot in middle) to a partially made protein (green). The complex binds the ribosome (white).
Image credit: Janet Iwasa, Ph.D., University of Utah
Shen, Frost, Brandman, and Weissman conducted the work in collaboration with colleagues at the University of Utah (Krishna Parsawar, James Cox), University of California at San Francisco (Xueming Li, Yifan Cheng, Matthew Larson), Stanford University (Joseph Park), and the University of Texas at Austin (Yidan Qin, Alan Lambowitz).
The research was supported by grants from the Searle Scholars program, the National Institutes of Health, the Howard Hughes Medical Institute, Stanford University, and the University of Utah.
Rqc2p and 60S ribosomal subunits mediate mRNA-independent elongation of nascent chains. Peter S. Shen, Joseph Park, Yidan Qin, Xueming Li, Krishna Parsawar, Matthew H. Larson, James Cox, Yifan Cheng, Alan M. Lambowitz, Jonathan S. Weissman, Onn Brandman, Adam Frost. Science, Jan. 2, 2015