Cell structures known as box C/D guide ribonucleoproteins (RNPs) help to maintain the integrity of ribosomes, which synthesize proteins in all forms of life on Earth (see related story).
A team in the lab of Susan J. Baserga, M.D., Ph.D., used electron microscopy to discern the structure of the box C/D RNP in Methanocaldococcus jannaschii, a hardy microbe found in Antarctic ice and in boiling vents on the ocean floor.
Conventional models have proposed that box C/D RNPs are composed of one RNA molecule and pairs of core proteins. But as reported in the September 11 edition of Science, first author Franziska Bleichert, M.D., and the Yale group found that the M. jannaschii box C/D RNP was instead made up of two RNAs and four copies of each of the three core proteins (see image above).
It looks like a Wheat Thin with feet,” says Baserga, professor of molecular biophysics and biochemistry. “When you can discern structure, you can often figure out function.”