Name: protein folding levels and bonds
Uploaded: 2023-04-30T10:34:07.000Z
Duration: 1 min 24 s
Channel: JoVE

K12 Standards

Next Generation Science Standards

High School

Life Science

from-molecules-to-organisms-structures-and-processes

From Molecules to Organisms: Structures and Processes

HS-LS1-1

Protein Organization

During translation, a chain of amino acids emerging from the ribosome forms the primary protein structure. This peptide chain is held together by covalent bonds between two amino acids&#39; amino and carboxyl ends.
Some amino acids make hydrogen bonds with their neighbors to form stable secondary structures such as alpha helices and beta-sheets.
Alpha-helices are spiral structures held together by hydrogen bonds between the carbonyl oxygen and amide hydrogen of every fourth amino acid residue of a polypeptide chain.
Beta-sheets are zigzag polypeptide structures formed when sections of the polypeptide chain interact sideways through hydrogen bonding.
Additional chemical interactions between distant amino acid side chains or the peptide backbone, such as hydrophobic forces, ionic bonding, and disulfide bridges, help the polypeptide fold into the tertiary structure. This 3D shape is the final functional form for many proteins.
If two or more polypeptide chains combine from the tertiary structure into a larger complex, a quaternary structure is created. These can be homomeric or heteromeric complexes with distinct cellular functions.

protein organization

Proteins are polymers of amino acid residues. They are versatile and responsible for different cellular functions, including DNA replication, molecular transport, catalysis, and structural support. Proteins have a hierarchical structure comprising at least three levels of organization: primary, secondary, and tertiary structure. Some large proteins have a quaternary structure where individual protein subunits are linked together.
The primary structure of a protein is its amino acid sequence. Amino acids are linked through peptide bonds to form a polypeptide chain with two ends: the amino terminus (N-terminus) and the carboxyl terminus (C-terminus). The sequence of amino acids determines the final folded form of the protein. Twenty different amino acids are arranged in different sequences to create a variety of polypeptides.
The secondary structure refers to locally folded regions of amino acid chains that are stabilized by hydrogen bonds. There are two types of secondary structures: alpha-helices and beta-pleated sheets. These secondary structural elements are connected by simple loops.
As the secondary structures assemble further, the final folded form of the protein is generated. Such a three-dimensional or tertiary structure of a protein is stabilized by the interactions between amino acid side chains. Hydrogen bonds, electrostatic forces, disulfide linkages, and Vander Waals forces stabilize the folded form, which is often the native or functional state of the protein.
When two or more folded polypeptide chains called protein subunits form a complex, a quaternary protein structure is created.&#160;

Proteins are polymers of amino acid residues. They are versatile and responsible for different cellular functions, including DNA replication, molecular ...

Education

JoVE Core

Cell Biology

Unit 1

Protein Structure

KEY TERMS AND CONCEPTS

protein folding levels and bonds

Proteins are built from amino acids and folded into shapes that support many cell jobs. They help with DNA replication, molecular transport, catalysis, and structural support. Their function depends on how their amino acids are arranged and folded.

Protein structure is organized in levels. The primary structure is the amino acid sequence in a polypeptide chain. Amino acids are joined by peptide bonds, and the chain has two ends: the amino terminus, or N-terminus, and the carboxyl terminus, or C-terminus. Twenty different amino acids can be arranged in many sequences to make a wide variety of polypeptides.

The secondary structure forms when parts of the chain fold locally. These regions are stabilized by hydrogen bonds. The two main secondary structures are alpha-helices and beta-pleated sheets. Simple loops connect these folded sections.

The tertiary structure is the full three-dimensional fold of one polypeptide chain. It is stabilized by interactions between amino acid side chains. Hydrogen bonds, electrostatic forces, disulfide linkages, and Vander Waals forces help hold the folded protein in its native, functional state.

Some proteins form a quaternary structure. This happens when two or more folded polypeptide chains, called protein subunits, join together into one complex. Large proteins can use this higher level of organization to work as a unit.

Protein Folding Levels and Bonds

what are proteins?

Protein Building Blocks and Folding

Proteins are built from amino acids linked by peptide bonds. Long chains of amino acids are often called polypeptides, and the terms proteins and polypeptides are sometimes used the same way. In this context, polypeptides with a molecular weight below 10,000 daltons are called polypeptides, while proteins have a higher molecular weight. Very short chains with fewer than 20 amino acids are called peptides or oligopeptides. Amino acids are the basic units of proteins. Each amino acid has a...

Proteins are built from amino acids and folded into shapes that support many cell jobs. They help with DNA replication, molecular transport, catalysis, and structural support. Their function depends on how their amino acids are arranged and folded. Protein structure is organized in levels. The primary structure is the amino acid sequence in a polypeptide chain. Amino acids are joined by peptide bonds, and the chain has two ends: the amino terminus, or N-terminus, and the carboxyl terminus, or...

protein folding

How Amino Acid Sequence Shapes Proteins

Proteins get their shape from the order of amino acids in a polypeptide chain. After a protein is made, the chain folds into a three-dimensional form that is needed for it to work. The way amino acids interact with one another guides this folding. Protein structure matters because proteins do many jobs in cells. They can speed up chemical reactions, help with immune defense, store materials, carry substances, send cell signals, support movement, and provide structure. A protein usually works...

protein families

Protein Families and Superfamilies

Protein families and superfamilies group proteins with shared features. These groups help scientists organize proteins by common structure, function, or evolutionary history. The classification can show how related proteins are connected across different organisms. A protein family usually includes proteins that are closely related. A superfamily is a broader group that can include several families with more distant relationships. These categories help explain why some proteins share similar...

conservation of protein domains

Protein Domains Shared Across Proteins

Protein domains are shared structural and functional parts of proteins. A domain is a region that can often be found in more than one protein, even when the full proteins are different. This conservation means that a protein domain may keep a similar shape or role across related proteins. Because of that, scientists can compare proteins by looking for domains that stay the same. Conserved domains help reveal how proteins are related and how they may work. The topic of protein domain...

globular and fibrous proteins

Protein Shapes: Globular vs Fibrous

Proteins can have globular or fibrous shapes, and these shapes help explain how they work in the body. Globular proteins are compact and usually fold into rounded forms. Fibrous proteins are long, extended molecules that often provide support and structure. The shape of a protein is tied to its function. Globular proteins often take part in chemical jobs in cells, while fibrous proteins are better suited for strength and stability. These structural differences make the two groups easy to...

intrinsically disordered proteins

Flexible Protein Regions and Disorder

Intrinsically disordered proteins have flexible regions that do not settle into one fixed shape. Instead, these proteins can remain dynamic and change form as they move through the cell. This flexibility is an important part of their structure and function. Many proteins need a stable folded shape to work properly. Intrinsically disordered proteins are different because they may lack a single rigid structure under normal conditions. Their shifting shape can help them take part in cell...

protein complex assembly

Protein Complex Formation and Function

Protein complex formation explains how proteins join together to carry out specific jobs in cells. These groups are called protein complexes, and they can form in more than one way. Some complexes are homomeric, which means they contain the same kind of protein subunit. Others are heteromeric, which means they contain different protein subunits. The assembly process helps show how protein shape and subunit choice affect function. When proteins combine, the resulting complex can behave...

conjugated proteins

Conjugated Proteins and Their Bound Groups

Conjugated proteins are proteins that include a nonprotein part called a prosthetic group. This added group helps give the protein its full structure or function. The video explains how the protein part and the bound group work together. Several common types of conjugated proteins are named by the kind of group attached. Nucleoproteins contain nucleic acids. Glycoproteins contain carbohydrate groups, and lipoproteins contain lipid groups. Other examples include phosphoproteins, which have...

amyloid fibrils

Amyloid Fibrils and Protein Aggregation

Amyloid fibrils are protein aggregates with a very specific structure. They are made when proteins misfold and stick together in long, ordered fibers. This structure makes them different from many other protein clumps. Amyloid fibrils are important in biology because they are linked to protein aggregation. Protein aggregation means proteins build up into groups instead of staying properly folded and separate. In many cases, this process is associated with disease and abnormal cell function. <br...

key terms and concepts

Explore protein folding from amino acid sequence to alpha-helices, beta-pleated sheets, tertiary shape, and quaternary protein subunits.

Protein Folding Levels and Bonds | JoVE K12

cell biology

JoVE Core Cell Biology illustrates complex cellular processes in easy-to-understand yet comprehensive animated video lessons. This collection focuses on the essential components and functions of cells, including organelles and membranes, cellular transport, and cell energetics. It is complemented by scientist-in-action videos that demonstrate the application of cell biology in real-world research experiments.

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Cell Structure

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Translation

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Protein Complex Assembly

Protein and Protein Structures

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Proteins: From Genes to Degradation

Amyloid Fibrils

What are Proteins?

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Protein Folding

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Conserved Binding Sites

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protein-complexes-with-interchangeable-parts

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Construct an explanation based on evidence for how the structure of DNA determines the structure of proteins, which carry out the essential functions of life through systems of specialized cells. [Assessment Boundary: Assessment does not include identification of specific cell or tissue types, whole body systems, specific protein structures and functions, or the biochemistry of protein synthesis.]

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structural-organization-of-the-human-body-an-overview

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Homeostasis
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Develop and use a model to illustrate the hierarchical organization of interacting systems that provide specific functions within multicellular organisms. [Clarification Statement: Emphasis is on functions at the organism system level such as nutrient uptake, water delivery, and organism movement in response to neural stimuli. An example of an interacting system could be an artery depending on the proper function of elastic tissue and smooth muscle to regulate and deliver the proper amount of blood within the circulatory system.] [Assessment Boundary: Assessment does not include interactions and functions at the molecular or chemical reaction level.]

HS-LS1-2

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Plan and conduct an investigation to provide evidence that feedback mechanisms maintain homeostasis. [Clarification Statement: Examples of investigations could include heart rate response to exercise, stomate response to moisture and temperature, and root development in response to water levels.] [Assessment Boundary: Assessment does not include the cellular processes involved in the feedback mechanism.]

HS-LS1-3

Protein Folding Levels and Bonds

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