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Transcript of Protein
Bio 111 NE1
Feb 5, 2010 Form and Function of the Building blocks for life Overview functions Sources Structure Protein: A Protein is a polymer macromolecule
that is created from one or more polypeptides
folded into unique 3D structures. Please explain!
Everything starts with an assortment of specially arranged organic molecules of key chemical groups. On each of these molecules, you have an Amino group (-NH2) on one side and a Carbolyxic Acid Group (-COOH) on the other. In the middle you have a carbon skeleton that also adds a side chain of additional molecules. This arangement is known as an.... AMINO ACIDS! There are
20 Different Amino Acids
(Remember them all!) Dehydration Reaction! Note that in the above diagram, the pink boxes denote
the Amino and Carboxyl ends. the structures on the blue field are the unique R structure of each amino acid group. Each amino acid monomer is a small building block.
Think of them as something similar to molecular Legos.
However, each brick by itself is pretty boring. They dont do anything!
The first step in making them do something is a.... ProTeins ProTeins ProTeins ProTeins ProTeins ProTeins ProTeins ProTeins ProTeins ProTeins ProTeins ProTeins ProTeins ProTeins Structures cells The dehydration reaction allows the linking of individual amino acid molecules into a polymer chain. a molecule of water is shed in the process, leaving a "peptide bond" in between the ends.
Polymer chains of Amino acids are normally called polypeptides. Do you remember those 20 amino acids? It all starts with special protein monomers. These monomers all have a similar shape, with a special set of side chains that make them unique.
The primary atoms in a protein monomer are Carbon, Nitrogen, Hydrogen, Oxygen, and also Sulfur.
These protein monomers are called... Those 20 molecules can be linked, end to end, in exponential ways.
More importantly, all the side molecules of the polypeptide sets the stage for the way the molecule will shape itself.
Each individual link in a polypeptide chain offers 20 different variations. a simple 5 link chain has 3.2 million theoretical variations.
The results can be amazing. even more amazing, they are part of you! Form allows funtion. Before we get to abilities,
we have to have complex 3D shapes Summary: remember that water will be shed at each peptde bond. - H2O! -H2O! -H2O! -H2O! -H2O! -H2O! -H2O! -H2O! -H2O! -H2O! -H2O! Do you remember this chain? That chain would represent a proteins... primary structure! A primary structure is simply the sequence of the individual amino
acids. Some polypeptides can be made up of a few peptide links, but
many of them can stretch for links of thousands of monomers! Do you remember those 20 Amino Acids from part 1? Due to all their outer valence electrons being pulled to one side of the atom for the covalent bonds, you have an assortment of electronegative oxygen atoms as well as weakly positive hydrogen atoms scattered throughout the chain. these act like little magnets... CH2 | SH In addition, each and every one of those amino acids has a little something unique going on in its R-group sidechain. Here is one example, Cysteine.
These R groups interact as well... | ALL OF THESE INTERACTIONS DETERMINE THE 3D SHAPES! To Form Secondary structures! The alpha helix is a spiral shape that comes as a result of weak magnetic bonding between those hydrogen and oxygen atoms.
As you can see, it twists the polypeptide by making a connection at every twist with another amino acid exactly 4 steps back (shown with the purple lines.)
Just like this
ALPHA HELIX! and also like this
BETA PLEATED SHEET! The beta pleated sheet looks just like a hairpin and also happens as a result of weak magnetic bonding between those hydrogen and oxygen atoms.
As you can see, it makes a kinky chain when two sections of the polypeptide sit side by side.
-H2O! -H2O! To Form Tertiary structures! Here are a number of ways in which tertiary structures can be created as a result of the interactions between R-groups.
Some amino acid R groups are non-polar, and will cluster together away from the water.
Others have ends composed of anions and cations, and will attract towards counterparts to form ionic bonds.
Finally, some will attract using yet more hydrogen bonds, but in the R-group instead of the backbone.
Tertiary Structures can get quite complicated! Tertiary structures take up space in very specific shapes which are unique to each amino acid sequence.
These shapes are highly specialized to individual tasks, and the codes for their specific arrangements are contained in DNA.
When compiled into a tertiary structure, a single polypeptide can be considered a protein, but most of the time you have groups of multiple polypeptides.
These are known as...
quaternary structures! Quaternary structures are formed by aggregations of tertiary polypeptides.
They can form all sorts of unique macromolecule clusters, which are tasked to do all sorts of great things in our bodies (and the bodies of all other living things)
This is a hemoglobin protein, which carries oxygen in red blood cells. we saw one of its tertiary components in the last slide. Here is another drawing of a hemoglobin protein.
The 4 different colors signify the individual polypeptides, and you can see all the coils and clusters that make up the secondary and tertiary structures
Summary: Now that we know how polypeptides are built, lets take a
look at some key finished proteins and the things they do! Summary: Mostly, you are what you eat.
RAW EGGS AND
WITH EGG PARTS Egg whites (Albumin) contain a good deal of protein as a direct animal source. In addition, As you cook an egg, the clear runny portion turns white. This is a great visual example of the denaturation process in action. Its now biologically inactive protein.
Once an egg is cooked, it cannot be "uncooked!" (but it can be eaten and its proteins broken down for our bodies to use)
Trivia: as a key component to breadmaking, egg is the binding that keeps the egg dough sticky during the rising process.
WHOLE GRAINS Nuts, Legumes, & Whole Grains are the dry, hard fruits and seeds of a number of plant species. The cultivation of legumes and grains was a key factor in the rise of modern human civilization.
In addition, legumes fix nitrogen in the earth, keeping the land fertile for grain crops.
Today, most of the world population continues to subsist primarily on this grain group as the major protein source in their diet. ANIMAL
MUSCULATURE We're talking about Steaks, Burgers, Chicken Breasts! Animal Proteins are one of the major components of the postindustrial* diet. There are no major differences between the proteins of animal and plant sources, but humans tend to enjoy the taste.
There are ethical concerns with our ability to sustain our present levels of consumption, yet consumption continues to rise.
*modern doesn't correlate with better, but it's tasty. that make up me, you, and all living things. The END. That make up the... and that's the story of ProTeins ProTeins that literally starts off small but grows... into... Transthyretin (TTR) Transthyretin (TTR) is a serum and cerebrospinal fluid carrier of the thyroid hormone thyroxine (T4) and retinol. This is how transthyretin gained its name, TRANSports THYroxine and RETINol Collagen Collagen is the main protein of connective tissue. It is also the most abundant protein in mammals, making up about 25% to 35% of the whole-body protein content.
In muscle tissue it serves as a major component of endomysium. Collagen constitutes 1% to 2% of muscle tissue, and accounts for 6% of the weight of strong, tendinous muscles. Gelatin, which is used in food and industry, is derived from collagen.