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Name: Massiel
Status: Student
Grade:  9-12
Location: N/A
Country: United States
Date: January 2009

What is it about proteins that allow for some many potential functions? Twenty amino acids and seemingly unlimited life functions?

If the average protein is around 150 amino acids long and there is no restriction on amino acid sequence, the number of different proteins possible would be larger than the estimated number of atoms in the universe.

Ron Baker, Ph.D.

Think of amino acids as a 20 letter alphabet. Each protein is a textbook. There are some grammar rules about how to construct "words", "phrases", "sentences", "paragraphs", "pages", and "chapters" of a "textbook". Change any one of the above results in a different "textbook" even after the grammar rules have to be obeyed. Some "textbooks" can be longer or shorter, and even some of its components can be different. Without doing a calculation it is clear that there are an enormous number of combinations of this 20 letter alphabet, even if there are a large number of possible "textbooks" possible, that do not "survive". Those combinations that don't replicate, or those that don't survive their environment, fail. Even so the number of possibilities are a very large number. That is how "evolution" selects combinations that survive, or adapt to different parts of the "textbook".

Vince Calder

If you think about the amino acids being like letters in the alphabet, there are many many words that can be created with just 26 letters, depending on how they are arranged. The slightly different chemical characteristics of the various amino acids are what determine the chemical behavior and functions of the proteins created from them when arranged in different sequences.


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