Collagen Webquest

COLLAGEN STRUCTURE AND FUNCTION

Proteins are the most diverse class of biological molecules. Most of your body is made up of proteins. Each protein consists of one or more polypeptide chains, in which amino acids are strung together in a specific order. This amino acid sequence or 'primary structure' is the key to the shape and function of the protein. Interactions among different amino acids along the length of the polypeptide chain cause it to coil, bend, and fold into a complex shape. Some proteins consist of two or more polypeptide chains. In many cases, the polypeptide chains form a rounded or globular shape. Most enzymes are like this, as is the oxygen-carrying hemoglobin molecule. In other cases, polypeptide chains form long strands or sheets. These fibrous proteins are often structural components, such as keratin and collagen.

Activity

In this activity, you will explore the structure and function of collagen, the most abundant protein in the human body. You will begin by visiting a Protein Data Bank site, where the structure of collagen is described and illustrated in a "Molecule of the Month" feature. Next, you will research the effects of osteogenesis imperfecta (OI), a genetic disorder that affects the structure or number of collagen molecules.

Part 1.

Use your browser to go to http://www.rcsb.org. This site is a Protein Data Bank where you can search for any information about your favorite proteins, including everyone’s favorite, collagen.

Do a search at the very top of the page for collagen, then click on the Molecule of the Month: Collagen link to view the article on collagen.

Read the information and view the graphics. Use this information to answer the following questions:

1. Describe the primary structure of collagen. What are the major amino acid components in collagen? The major components of collagen is 1400 amino acids with every third being glycine. The major components in collagen are glycine, proline, and hydroxyproline. These three components create the sturdy structure for when they reapeat.





2. What role does vitamin C play in collagen formation? What happens when a person does not get enough vitamin C in his or her diet? The role Vitamin C assists the reaction that takes place with normal proline for it to become hydroxyproline. When you don’t get enough vitamin C in your everyday diet it will result in the slow production of hydroxyproline and therefore the construction of collagen resulting with scurvy. Pirates had scurvy because of not enough Vitamin C there diet.





3. Describe the quaternary structure of collagen (the way in which the polypeptide chains are arranged). The quaternary structure of collagen is three polypeptide chains mixed into a triple helix. In the middle of the helix glycine settles, while an non-common amino acid-proline and its modified to form hydroxyproline witch is pressed tightyly around the structure.




Part 2.

Use your browser to go to the Web site of the Osteogenesis Imperfecta Foundation at

http://www.oif.org

On the left side of the home page, click the link “About OI”, then find the “Facts About OI” section.

Read the material in the sections entitled "Facts on Osteogenesis Imperfecta” and “Types of OI.” Use what you have learned to answer the following questions:

1. What is the main symptom of osteogenesis imperfecta? What are some other symptoms that people with OI may have? The main symptom of osteogenesis imperfecta is fragile bones that crack and fracture easily. Other symptoms that people with OL may experience are muscle weakness, fatigue, joint laxity, hearing loss, short stature, and curved bones.







2. Type I osteogenesis imperfecta causes fewer problems than the other forms. How does the collagen structure in Type I OI differ from that of the other types?
The structure is diffrent because those with type 1 have spontaneous mutation while others have a dominant mutation to one set of collagen genes.







Read the handout (pdf) in the resources section on Bone Structure.

1. Describe the role of collagen in bones. Why do collagen problems lead to bone problems?
The role of collagen in bones is like steel reinforcement in concrete. Minerals such as phosphorus and calcium crystallize around the collagen and provide strength. The collagen in the middle provide the resiliency and flexiblitlity in bone that is needed to withstand trauma or daily uses. Collagen problems lead to bone problems because not having enough collagen or the wrong kind of collagen to be able to provide the bone with flexibility and durability. You are more likely to get more breaks or fractures of the bone.