New identified code helps to explain formation of certain cells

We know that human body is made up of trillions of cells and each cell contains thousands of proteins, which determine how the cell is formed and what functions it will perform. Proteins are made up of hundreds of amino acids. The blueprint for each protein is specified by genetic codons, which are triplets of nucleotides that can make 20 different types of amino acids. How amino acids are linked together determines which proteins which proteins are produced, and then what functions the cell will have.
UT Southwestern physiologists have found a new code that helps explain which protein should be created to form a particular type of cell. They got the concept that the sequence of the amino acids and the speed of the process in which the amino acids are put together into a functional protein both matter. The new 'code' within the genetic code uncovers an important regulatory process that impacts all biology, according to Dr. Yi Liu, Professor of Physiology.
Almost every amino acid can be encoded by multiple synonymous codons and that every organism, from humans to fungi, has a preference for certain codons. It was found that if more frequently used codons, they will speed up the process of producing an amino acid chain, while less frequently produced codons slow the process. The use of codons seems to have speed signs on the protein production. That's to say, some segments need to be made fast and others need to be slow.
 "The genetic code of nucleic acids is central to life, as it specifies the amino acid sequences of proteins," said Dr. Liu, the Louise W. Kahn Scholar in Biomedical Research. "By influencing the speed with which a protein is assembled from amino acid building blocks, the use of "fast" and "slow" codons can affect protein folding, which is the process that allows a protein to form the right shape to perform a specific function. This speed control mechanism makes sure that proteins are assembled and folded properly in different cells. Therefore, the genetic code not only specifies the sequence of amino acids but also the shape of the protein."
The researchers also found that proteins with identical amino acid sequences will have different functions if they are assembled at different speeds. This is of great importance to identify human disease-causing mutations, for they think a mutation doesn't have to change amnio acid identity to cause a disease.
The study was published in the journal Molecular Cell as the cover story. You can get more detail information there.
Read more:http://about.cusabio.com/m-170.html