A protein has several different levels of structure. The primary structure is the arrangements of atoms and bonds, and it is formed in the ribosome by the assembly of amino acids as directed by an RNA template. The secondary structure is the local topology, the helices and strands, and this forms mostly because of the release of energy through the formation of hydrogen bonds. The tertiary structure is the actual fold of the protein, the way helices, strands, and loops are arranged in space. The fold forms primarily because of the favorable entropy of burying the protein's hydrophobic groups where water cannot access them, analogous to the formation of an oil droplet in water. This suggests that, in addition to the well-known phenomenon of proteins denaturing, or losing their higher-order structure, under conditions of high heat, proteins might also denature when they get too cold.The proposition that general fold architecture is preserved within a family of evolutionarily-related proteins is not controversial. The amino acid sequence of a protein determines its structure, and countless studies have substantiated the idea that proteins with similar sequences will adopt similar folded conformations. Because structure and dynamics are intrinsically linked, one could reasonably assume that many features of a protein's dynamics get conserved along with the fold. A growing number of experiments show that this is indeed the case, including a recent paper in Structure (1).Alert your labmates
if your prep will require all
the lab's baffled flasks.
Refill or reorder
reagents before you empty
the goddamn bottle.
Touching toxins, gloves
go on. Touching telephones,
take those nasty things off.
Read the rest...
Final Status: Complete.
Put this on your box: It's Star Fox without anything that you liked about Star Fox!
The ultimate Camp statement: it's good because it's awful. ...Of course, one can't always say that.
—Susan Sontag, "Notes on 'Camp'"
This game is so bad, it's not just become good. It's pretty close to perfect.
—Jim Sterling, review of Deadly Premonition
Spongiform encephalopathies are transmissible diseases that can have a major economic impact on agricultural exports, and pose a significant challenge for surveillance of the food supply. Scientists generally believe that these diseases are transmitted via a self-propagating, aberrant conformation of the prion protein (PrP). This prion hypothesis suggests that PrP alone should be sufficient to cause symptoms or death. If this hypothesis is true, then it should be possible to reproduce the disease using recombinant proteins expressed in yeast or bacteria. In tomorrow's Science, researchers from Columbus and Shanghai report that they have managed to do this, establishing that PrP alone can account for prion disease transmission.
