Protein Factories

Every ceU—whether bacterium, yeast, plant, insect, or human—is a protein factory, among other things. CeUs produce the proteins for... 

In a nutshell, RNA transcribes the genetic code of the DNA, and transfers it to the cell s protein factories. This process also requires a shearing and splicing of the RNA molecules, because DNA strands contain regions which are not essential for... 

Sitia, R., and Braakman, I. (2003). Quality control in the endoplasmic reticulum protein factory. Nature, 426, 891-894. 

Two other viral vectors are extensively used. Vaccinia virus, a large DNA-containing virus, replicates in the cytoplasm of mammalian cells, where it shuts dovm host-cell protein synthesis. Baculovirus infects insect cells, which can be conveniently cultured. Insect larvae infected with this virus can serve as efficient protein factories. Vectors based on these large-genome viruses have been engineered to express DNA inserts efficiently. 

The largest dairy company in Denmark, called "Dairy Denmark" is, as far as I know, the most progressive one in the world today with regards to the production of whey proteins by means of ultrafiltration. Figure 5 is a photo of a quite new protein factory, called "Denmark Proteins", whose sole purpose is to ultrafiltrate... 

The basic unit of life, these tiny sacs contain chromosomes and protein factories, among other elements. 

Giddings G. Transgenic plants as protein factories. Curr. Opin. Biotechnol., 2001 12(5) 450-454. 

Ribosomes. Ribosomes are the protein factories. They are particles consisting of proteins and another type of RNA called ribosomal RNA (rRNA). The fact that ribosomes are the loci of protein synthesis was only discovered in the early 1950s as a result of incorporation studies with radioactively tagged amino acids. Now, ribosomes are known to be large ribonucleoprotein particles on which the message carried by mRNA is translated into the protein s amino acid sequence. 

Borman, Stu. Protein Factory Reveals Its Secrets. Chemical if Engineering News 85 (February 19, 2007) 13-16. This is an accessible discussion of the structural biology of the ribosome at the atomic level. 

Since we cannot make tryptophan, we need to consider what happens if we cannot obtain it. Will our protein factories perhaps substitute a similar amino acid and keep going, or will they just skip one position The answer is that everything will grind to a halt. The whole basis of the protein synthetic machinery is that it is incredibly specific and unerringly puts in the right amino acid (see Topic 35). Its job is not to be imaginative and resourceful, merely to carry out orders However, it can only do so if provided with the necessary raw materials. So, if the right amino acid is not there, the process simply caimot proceed. 

Hempel, F., Lau, J., Klingl, A., and Maier, U.G. (2011) Algae as protein factories expression of a human antibody and the respective antigen in the diatom Phaeodactylum tricornutum. PLoS One, 6 (12), e28424. 

Antimalarial drug artemisinin has been produced from metabolically engineered laboratory yeast. The antimalarial comes from the Artemisia annua plant, which grows in Southeast Asia. Artemisinin could also possibly be used in cancer treatment. Scientists are able to synthesize large DNA molecules in the laboratory. Researchers have made artificial DNA containing all twenty-one genes encoding the small ribosomal subunit (cell protein factory) from Escherichia coli (E. colt). 

The lymphocytes are responsible for our immune system that protects us from disease. These cells are active protein factories and have a large nucleus that almost completely fills the cell. The small amount of cytoplasm contains the factory components for making and secreting immune proteins. 

PROTEINS are polymers of amino acids joined by peptide bonds (proteins are therefore also known as polypeptides). The number and order of the amino acids contained in a particular protein are prescribed by the DNA sequence of that protein s gene. The mechanism by which a genetic message is translated from its nucleic acid form to its polypeptide product is protein synthesis. Translation occurs at the ribosome, an RNA-protein complex often called the protein factory of the cell. 

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