Hey, everyone. So in this video, we're going to take a look at a summary of our different protein structures. Now, we're going to say that proteins are very complex molecules with four levels of structural organization. In the first one, we're going to talk about our primary structure. Now, remember, the characteristics of our primary structure is that it's just a sequence of our amino acids. All these amino acids are linked together or stabilized by peptide bonds. Next, we move on to our secondary structure. We're still dealing with our same peptide chain, and we're going to say this peptide chain can basically coil upon itself to create alpha helices, or it can basically orient itself where we create beta pleated sheets. Now, here we're going to say the characteristics here is that it's a spatial arrangement of the polypeptide chain. Here, we're going to see that it's stabilized by the fact that we have hydrogen bonds between the backbone atoms. Next, we move on to our tertiary structure. Here we have our hydrophobic interactions that kind of cause the peptide chain to turn in on itself, where the hydrophobic portions will be on the interior of the chain. Now, here we're going to say the overall shape of the folded polypeptide chain is the characteristics when it comes to the tertiary structure. Now, here we're going to say that it's stabilized by, we're going to say that it's stabilized here by four non-covalent interactions and one covalent bond. The four non-covalent interactions include hydrophobic interactions, as well as hydrophilic. So the hydrophobic portions will orient themselves on the interior of our chain, and the hydrophilic portions, which like water, would orient themselves on the outside. Now, in addition to this, we have hydrogen bonding involved and then our salt bridge. Our covalent bond is when we have our disulfide bridge. Finally, we have our quaternary structure, which is the most complex level of our protein structure. We're going to say this is the association of two or more subunits. So remember, just think of the quaternary structure as building on top of the tertiary structure. We'd have multiple polypeptide chains coming together to form this fully functional protein. Now, here we're going to say because it is building off of the tertiary structure, we're going to say that it's stabilized by the same interactions as in a tertiary structure. So this is what we can say in summary when it comes to organizing proteins, all the way from the primary structure up to the quaternary structure.
Summary of Protein Structure - Online Tutor, Practice Problems & Exam Prep
Summary of Protein Structure Concept 1
Video transcript
Summary of Protein Structure Example 1
Video transcript
Here in this example question, it says, determine whether each of the following statements describes the primary, secondary, tertiary, or quaternary structure of a protein. For the first one, it says, side chains interact to form disulfide bonds. So remember, disulfide bonds are a key characteristic of a tertiary structure. So here, this represents a tertiary structure. Next, peptide bonds join amino acids into a polypeptide chain. This is how we begin our journey towards a fully functional protein. This represents our primary structure. Remember, amino acids form these peptide bonds with one another, forming and linking together to form a long peptide chain.
Next, two peptide chains are held together by hydrogen bonding. Alright. So they're talking about two chains. Now here, that couldn't be primary or secondary. Because remember, those happen amongst one chain. So that means it's either going to be tertiary or quaternary. Here they're saying two polypeptide chains are held together by hydrogen bonding. This has to be a quaternary structure because here we can have these types of interactions that connect different chains with one another, Eventually, this will lead up to our quaternary structure later on.
Next, hydrogen bonding between amino acids in the same polypeptide gives a coiled shape to the protein. Coiled shape is a reference to our alpha helices or alpha helix. Remember, that is indicative of a secondary structure. So this will represent our different types of protein structures based on these four statements.
Determine which of the following statements describes a tertiary structure of a protein.
Three polypeptide chains interact to form a biologically active protein.
Hydrogen bonds form between adjacent segments of the backbones of the same protein to form its creased structure.
Nonpolar side chains are repelled by water and move to the interior of the protein.
Amino acids react in a condensation reaction to form a peptide bond.
Indicate whether each of the following statements describes a primary, secondary, tertiary, or quaternary protein structure:
______ a) Hydrophobic R groups seeking a nonpolar environment move toward the inside of the folded protein.
______ b) Protein chains of collagen form a polypeptide chain composed of 3 alpha helices.
______ c) An active protein contains 4 tertiary subunits.
______ d) Two polypeptide chains held together by disulfide bridges.
Problem Transcript
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- How do the following noncovalent interactions help to stabilize the tertiary and quaternary structure of a pro...
- How do the following interactions help to stabilize the tertiary and quaternary structure of a protein? Give a...
- A portion of a polypeptide chain contains the following sequence of amino acids: —Leu—Val—Cys—Asp— a. Which am...
- A portion of a polypeptide chain contains the following sequence of amino acids:—Leu—Val—Cys—Asp—c. How does t...
- Indicate whether each of the following statements describes primary, secondary, tertiary, or quaternary protei...
- Indicate whether each of the following statements describes primary, secondary, tertiary, or quaternary protei...
- Indicate the changes in secondary and tertiary structural levels of proteins for each of the following:b. Prio...
- Indicate the changes in secondary and tertiary structural levels of proteins for each of the following:c. To a...
- b. Would you expect to find this segment at the center or at the surface of a protein? Why?
- Consider the amino acids lysine, valine, and aspartate in an enzyme. State which of these amino acids have R g...
- Consider the amino acids lysine, valine, and aspartate in an enzyme. State which of these amino acids have R g...
- Consider the amino acids lysine, valine, and aspartate in an enzyme. State which of these amino acids have R g...
- Classify each of the following proteins according to its function:a. hemoglobin, oxygen carrier in the blood
- Classify each of the following proteins according to its function:c. keratin, a protein found in hair
- Classify each of the following proteins according to its function:a. insulin, a protein needed for glucose uti...
- Classify each of the following proteins according to its function:c. casein, milk protein
- List the type of attractive force disrupted and the level of protein structure changed by the following denatu...
- Identify each of the following statements as characteristic of protein denaturation or protein hydrolysis. a. ...
- Identify each of the following statements as characteristic of protein denaturation or protein hydrolysis. b. ...
- Identify the level of protein structure associated with each of the following:d. salt bridges between polypept...