What is a Protein?


Proteins play countless roles throughout the
biological world. Some transport nutrients throughout the body. Some help the chemical reactions happen at
a faster rate. Others build the structures of the living
things. Despite this wide range of functions, all
proteins are made out of the same 21 building blocks, called amino acids. Amino acids are made of carbon, oxygen, nitrogen,
and hydrogen, and some contain sulfur atoms. Selenocysteine is the only standard amino
acid that contains a selenium atom. These atoms form an amino group, a carboxyl
group, and a side chain attached to a central carbon atom. The side chain is the only part that varies
from amino acid to amino acid and determines its properties. Hydrophobic amino acids have carbon-rich side
chains, which don’t interact well with water. Hydrophilic or polar amino acids interact
well with water. Charged amino acids interact with oppositely
charged amino acids or other molecules. Primary Structure
The primary structure of a protein is the linear sequence of amino acids as encoded
by DNA. The amino acids in a protein are joined by
peptide bonds, which link the amino group of one amino acid to the carboxyl group of
another. A water molecule is released each time a bond
is formed. The linked series of carbon, nitrogen, and
oxygen atoms make up the protein backbone. These protein chains often fold into two types
of secondary structures: alpha helices, or beta sheets. An alpha helix is a right-handed coil stabilized
by hydrogen bonds between the amine and carboxyl groups of nearby amino acids. Beta-sheets are formed when hydrogen bonds
stabilize two or more adjacent strands. The tertiary structure of a protein is the
three-dimensional shape of the protein chain. This shape is determined by the characteristics
of the amino acids making up the chain. Many proteins form globular shapes with hydrophobic
side chains sheltered inside, away from the surrounding water. Membrane-bound proteins have hydrophobic residues
clustered together on the outside, so that they can interact with the lipids in the membrane. Charged amino acids allow proteins to interact
with molecules that have complementary charges. The functions of many proteins rely on their
three-dimensional shapes. For example, hemoglobin forms a pocket to
hold heme, a small molecule with an iron atom in the center that binds oxygen. Two or more polypeptide chains can come together
to form one functional molecule with several subunits. The four subunits of hemoglobin cooperate
so that the complex can pick up more oxygen in the lungs and release it in the body. Different visual representations of proteins
can give us visual clues about the protein structure and function. This space filling diagram shows all atoms
that are making up this protein. This representation, called ribbon or cartoon
diagram shows the organization of the protein backbone and highlights the alpha helices. This surface representation shows the areas
that are accessible to water molecules. Most proteins are smaller than the wavelength
of light. For example, the hemoglobin molecule is about
6.5 nanometers in size. Hemoglobin is found in high concentration
in red blood cells. A typical red blood cell contains about 280
million hemoglobin molecules. The three-dimensional shapes of proteins determine
their function. The flexible arms of antibodies protect us
from disease by recognizing and binding to pathogens and targeting them for destruction
by the immune system. The hormone insulin is a small, stable protein
that can easily maintain its shape while traveling through the blood to regulate the blood glucose
level. Alpha Amylase is an enzyme that begins digestion
of starches in our saliva. The calcium pump is aided by magnesium and powered by ATP to move calcium ions back to the sarcoplasmic reticulum after each muscle contraction. Ferritin is a spherical protein with channels
that allow the iron atoms to enter and exit depending upon organism’s needs. On the inside ferritin forms a hollow space
interior with atoms attached to the inner wall. Ferritin stores iron in the non-toxic form. Collagen forms a strong triple helix that
is used throughout the body for structural support Collagen molecules can form elongated fibrils
which aggregate to form collagen fibers. This type of collagen is found in skin and
tendons. Learn more about the functions and 3D structures
of proteins and other molecular machines at the RCSB Protein Data Bank.

Posts Tagged with…

Reader Comments

  1. RCSBProteinDataBank

    To contribute closed captions for this video in your language, use this link http://www.youtube.com/timedtext_video?v=wvTv8TqWC48&ref=share

  2. Jeremy Cornwell

    Carbon is hard to burn, sticks around. After softer tissue/aminos accumulated. Then bloat, water retention. Bounds to carbon.

  3. Rishika Kasera

    Your animation is too good but i m from other country and u should give in the below that what r u saying
    I am not understanding what r u saying

  4. SteadFast nEasy

    …… and this all came about from an electrical charge into a pool of inanimate chemicals. Riiiiiiight. I wonder if Evolutionists ever REALLY stop and think about what they're saying?

  5. QRS

    02:31 pump..
    02:57 hemoglobin (molecule) 03:53

    wikipedia.org/wiki/Hemoglobin
    rcsb.org/3d-view/1GZX
    proteopedia.org/wiki/index.php/Hemoglobin

  6. Disent Design

    so are proteins consider living things? what programed / set them up to behave so intelligently and intricately? surely trial and error / natural selection can not explain their apparent complex, intelligent-like behavior. I'm agnostic when it comes to things we cant know for sure such as the existence of some kind of intelligent creator / simulation designer but the more I learn about the details of the universe the more im convinced none of this just could've possibly just happened by accident….sure its possible we just happen to live in one of an infinite amount of varying universes that just happen to support life, but if thats the answer you need to explain all this than ask yourself why were an infinite amount of universes created in the first place.

  7. Rolf Krauss

    I’ve been studying nutrition/exercise science for the last decade and this beautiful video helped me conceptualize it all in a mind blowing way. I love you

  8. Michael Harris

    Thanks for relaying this information to the public. It's telling us about the magic of the world, more than we could have dreamed in our wildest dreams. That has to be good.

  9. Tips For Be Healthy

    Protein is very essential for the growth of the body, to repair damaged tissue, maintaining body functions and also mainly for the immunity system to protect you. Proteins are antibodies that kill bacteria, viruses, and fungi that enter the body. They need to produce hormones that need to the function of the body. Almost all the enzymes used to digest foods are produced from them. They also help to transport various substances and compounds through the blood. As an example, Hemoglobin is a protein that transports oxygen from the lungs to other cells. Therefore it is very important to take a necessary amount of protein from foods daily.
    https://www.tipsforbehealthy.com/healthy-ife/importance-of-having-protein-rich-diet/

  10. Dimitri

    How can we know so much about all this shit and still suffer the pitifully short lifespans that we do!? Some peeps believe in voodo magic. I believe in science so hurry the f up people!!!

  11. Dadson worldwide

    if the ocean was filled with amino acids and goven 4.6 billion years to rub together the odds of 1 randonmly coming together in the correct order is 10 to the 104 th power agaist it happening.
    thats just one lol.
    then its just as hi that they will randomly form 1 single protein this way.
    from the big bang all the way to the creation of life there is these millions of steps that each have these type of odds against each step taking place.
    so mathmatically improbable that these odds would force any theory or idea to ve concidered false.

  12. Salvatore Escoti

    The 3D structure of a protein is essential for it functionality. If a Protein is folded slightly wrong, it will make you really very sick.

  13. Yoso

    I don’t understand how it can be. So it must be gawd. I don’t understand how gawd can be either, so I’ll just say gawd has always been and always will be. There, that shows just how intelligent I am!! Or I could just say: Ain’t it fascinating!

  14. Coach Nick Hawley

    It's totally mind blowing to think about all the complexity involved in just living day to day. It makes me appreciate life more when I watch things like this. Thank you for putting the effort into this incredibly thoughtful video.

  15. moises alonso

    After watching this, who here still remains an atheist? I was to know… Because these molecules forming amino acids that come together to form proteins that in turn become cells… What necessitates this to happen? Do these molecules have a brain? What tells the molecule that they need to integrate with other molecules, what is the necessity? Why can't a molecule say fuck you, I don't want to be a part of a dinky heat shock protein, I want to fly to the moon instead, I know! Instead of building a boring amino acid, I will build myself some wings and fly off to the Galapagos…

  16. Hazwan Shah

    Waw..they look like super complex machine..makes it hard to believe that this kind of complexity can happen coincidentally..

    Thanks for the knowledge sharing..very interesting..

  17. John Murphy

    And people actually believe that this all happened by accident 😂 it's compelling how many real smart idiots there are in this fallen world.

  18. moises alonso

    I don't have to prove that God exists since the evidence is his creation. You on the other have to prove he doesn't exist despite the evidence that he does. You have it all backwards my man, academia is crumbling all over the place though, with your Cultural Marxism and climate change hoax nutjobs bringing the whole thing down. The emperor is bare naked and we are all laughing, only fools continue to compliment the Emperor's fabulous garments.

  19. GJZZTRRE TTMMGGRR ERTZHG YENARTD

    Thsnks Sir..💜❤💜❤💜❤❤💜❤💜❤💜💖💚💖💚💖💚💖💚💖💚💖💚💖💚💖💙💛💗💌❣💛💙💗💌❣💛💙💗💌❣💟💞

  20. 1 Negahe Digarr

    Those billions of atoms molecules and microorganisms are working so hard to keep me alive while I'm sitting idle and doing nothing .
    Shame on me .

  21. Sandra Aguilera

    Una maravillosa información de la minúscula proteína , y sobre todo el trabajo tan especial que hace.
    Use el traductor y lo miré muy despacio para poder entender el proceso que tiene.
    Aclaró , me gusta ver estos vídeos para entender un poco como funciona el organismo.
    Saludos.

Write a Comment

Your email address will not be published. Required fields are marked *