Department of Energy Argonne National Laboratory Office of Science NEWTON's Homepage NEWTON's Homepage
NEWTON, Ask A Scientist!
NEWTON Home Page NEWTON Teachers Visit Our Archives Ask A Question How To Ask A Question Question of the Week Our Expert Scientists Volunteer at NEWTON! Frequently Asked Questions Referencing NEWTON About NEWTON About Ask A Scientist Education At Argonne Protein Structure to Function
Name: Massiel
Status: Student
Grade:  9-12
Location: N/A
Country: United States
Date: January 2009


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



Replies:
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.

Don



Click here to return to the Molecular Biology Archives

NEWTON is an electronic community for Science, Math, and Computer Science K-12 Educators, sponsored and operated by Argonne National Laboratory's Educational Programs, Andrew Skipor, Ph.D., Head of Educational Programs.

For assistance with NEWTON contact a System Operator (help@newton.dep.anl.gov), or at Argonne's Educational Programs

NEWTON AND ASK A SCIENTIST
Educational Programs
Building 360
9700 S. Cass Ave.
Argonne, Illinois
60439-4845, USA
Update: June 2012
Weclome To Newton

Argonne National Laboratory