Name: antibody heavy and light chains
Uploaded: 2020-11-23T11:47:34.000Z
Duration: 1 min 10 s
Channel: JoVE

K12 Standards

Tennessee Academic Standards

High School

Biology

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

From Molecules to Organisms: Structures and Processes

BIO1.LS1.3

Antibody Structure

抗体也称为免疫球蛋白
 
 是针对外来抗原的
 
 体液免疫应答的关键参与者
 
 它们是由四个Y形结构的
 
 多肽组成的蛋白质
 
 具有两个相同的重链和两个相同的轻链
 
 通过非共价键和
 
 共价二硫键的组合连接在一起
 
 在每条多肽链的最尖端
 
 是选择性结合抗原的
 
 独特可变结构域
 
 虽然该区域的某些部分
 
 直接相互作用
 
 但其他部分为这些结合位点
 
 提供结构支持
 
 相反 抗体的茎区域
 
 称为恒定区
 
 根据类别确定特定的
 
 免疫作用机制
 
 例如 一种类型的免疫球蛋白E
 
 在体内响应过敏原
 
 如猫皮屑分泌
 
 并介导过敏反应

西尔弗顿，E.W.，MA Navia 和 DR Davies。"完整人类免疫球蛋白的三维结构。"美国国家科学院院刊 74，第 11 期（1977 年 11 月 1 日）:5140-44。[<a href="https://doi.org/10.1073/pnas.74.11.5140" target="__blank">来源</a>]

抗体结构

<h4>概观</h4>
抗体，也称为免疫球蛋白（Ig），是适应性免疫系统的重要参与者。这些抗原结合蛋白由B细胞产生，占总血浆重量的20％。在哺乳动物中，抗体分为五个不同的类别，每个类别在抗原结合时都会引发不同的生物反应。“
<h4>抗体的Y形结构由四条多肽链组成</h4>
 
 抗体由四个多肽链组成：两个相同的重链，每个约440个氨基酸，和两个相同的轻链，由大约220个氨基酸组成。这些链排列成Y形结构，由共价二硫键和非共价键结合在一起。此外，大多数抗体携带糖残基。向蛋白质中添加糖侧链的过程称为糖基化。
 
 <h4>抗体的亚单位有不同的功能</h4>
 
 轻链和重链都有助于Y结构每个末端的抗原结合位点。这些110-130个氨基酸是高度可变的，允许识别几乎无限数量的抗原。这个区域也被称为可变区，是抗原结合片段的一部分。
 
 Y形单元的每一个臂携带一个相同的抗原结合位点。抗体可以交联抗原：当一只手臂与一种抗原结合，而另一只手臂与另一种结构相同的抗原结合时。交联是由柔性铰链区促进的，该柔性铰链区将抗体和臂的连接到茎并允许抗原结合位点之间的可变距离。随后，大量的交联抗原被巨噬细胞更快、更容易地吞噬，同时清除大量的抗原。
 
 抗体的干区也称为片段可结晶（Fc）区，决定抗体的效应功能。通过Fc结构域，抗体可以与其它免疫细胞（如B细胞、巨噬细胞和肥大细胞）上的Fc受体相互作用。Fc区域通常是糖基化的，阻碍或允许Fc受体进入。因此，改变抗体的糖基化状态可以快速调节抗体功能。
 
<h4> 哺乳动物有五类抗体</h4>
 
 抗体按其Y形结构的数目和重链的类型分类。IgD、IgE和IgG类抗体具有单一的Y形结构，在其臂尖提供两个相同的抗原结合位点。更科学的说法是：它们的化合价是2。然而，IgD、IgE和IgG在其两个重链之间的二硫键和非共价键的组成上有所不同。IgA可以作为单体或二聚体出现，类似于在其基部连接的两个y。作为二聚体，IgA有四个相同的抗原结合位点，其价为四。IgM可以作为单体出现，但更常作为五聚体出现，使其化合价为10。
 
<h4> 五类抗体触发不同的免疫功能</h4>
 
 IgG抗体是血液中最丰富的抗体分子，在第二次遇到特定病原体时大量分泌。IgGs几种方面有助于病原体的清除。它们对病原体进行调理，以触发巨噬细胞或中性粒细胞的吞噬作用。这些吞噬细胞的活性被补体系统增强，补体系统是一系列酶蛋白。补体系统本身由IgG触发。此外，IgGs是唯一能从母体穿过胎盘到达胎儿的抗体。它们也会分泌到母乳中，从而提供被动免疫，保护婴儿免受感染。
 
 IgA保护粘膜表面，如胃肠道、呼吸道和泌尿生殖道。它最重要的是中和细菌，防止它们在上皮上移动。IgA也会分泌到粘液、眼泪、唾液和初乳中（母亲在分娩后的头几天乳腺分泌的富含抗体的物质）。IgA在分泌时以二聚体的形式出现，在体液中以单体的形式出现。
 
 IgM类的单体是第一个出现在原始B细胞上的。IgM是B细胞在第一次接触抗原（即主要抗体反应）时分泌的主要一类抗体。当抗原与IgM分子结合时，它激活补体系统并中和病原体。
 
<h4> IgD抗体的功能尚不清楚，但似乎与IgM相似。</h4>
 
 由于IgE在体液中的含量较低，研究起来很有挑战性，而且主要以其对人类健康的负面影响而闻名：过敏。在过敏反应中，IgE与其同源抗原结合。随后，IgE的Fc区与肥大细胞和嗜碱性粒细胞（一种白细胞）结合。IgE与细胞表面Fc受体的相互作用引起组胺和白细胞介素的释放，进而引起诸如喷嚏和瘙痒等过敏症状。
 
<h4> 用于研究、诊断和治疗的抗体在动物体内产生</h4>
 
 抗体是一个重要的工具，在许多研究学科，以及在诊断，有时治疗疾病。为了产生抗体，抗原被注射到农场或实验动物体内，通常是兔子、鸡、仓鼠或山羊，然后从动物血液中分离出来。

概述  
抗体，也称为免疫球蛋白（Ig），是适应性免疫系统中的关键成员。这些抗原结合蛋白由……产生

Education

教育

JoVE Core

Molecular Biology

分子生物学

Unit 1

第一单元

Protein Structure

蛋白质结构

KEY TERMS AND CONCEPTS

关键术语与概念

antibody heavy and light chains

Antibodies are built from heavy and light chains that work together to form a Y-shaped molecule. These chains give the antibody its basic structure and help it bind to specific targets.

The two upper arms of the Y contain the variable regions, which differ from one antibody to another. These variable regions help determine which antigen, or foreign molecule, the antibody can recognize.

The lower part of the antibody is the constant region. This region is more similar across antibodies and helps define the antibody class. The structure of the chains also supports the antibody’s overall shape and function.

Antibody Heavy and Light Chains

what are proteins?

Proteins, Amino Acids, and Polypeptides

Proteins are built from amino acids and form polypeptides. Amino acids are the small building blocks, and a polypeptide is a chain of amino acids joined together. This basic relationship explains how proteins are made and why their structure matters. Proteins have several important roles in living things. Some proteins help build body structures, while others carry out work inside cells. The transcript also connects proteins to enzymes, which are proteins that speed up chemical reactions.

protein organization

Protein Organization and Folding Levels

Protein organization describes how a protein is arranged at several levels. These levels help explain how a chain of amino acids becomes a working molecule. The main stages are primary, secondary, tertiary, and quaternary structure. Primary structure is the linear order of amino acids in the protein chain. Secondary structure is the first step of folding. In this stage, the chain can form patterns such as helices and sheets. Tertiary structure is the overall three-dimensional shape of one...

protein folding

Protein Folding and Structure

Protein folding is the process that gives a protein its final three-dimensional shape. That shape is essential because a protein’s structure helps determine how it works in the cell. A folded protein is stabilized by several interactions. These include hydrogen bonds, van der Waals interactions, and disulfide bridges. Each one helps hold the protein in the correct form. When a protein does not fold properly, its structure can change. That can affect its function and can interfere with normal...

conservation of protein domains over different proteins

conservation-of-protein-domains-over-different-proteins

Argonaute Protein Domains Across Species

Argonaute proteins have conserved domains that help small RNAs guide gene silencing. These proteins are found across organisms, but the number of Argonaute family members can differ from one species to another. Protein domains are small, structurally independent parts of a single amino acid chain. They can keep their shape on their own, but they may still work together with other parts of the protein. During evolution, domains can duplicate, recombine, and form new combinations. This process,...

globular and fibrous proteins

Protein Shapes: Globular vs Fibrous

Proteins can be grouped by shape into globular proteins and fibrous proteins. These two subtypes also differ in how they dissolve in water and in the jobs they do in cells and tissues. Globular proteins, also called spheroproteins, are usually round in shape. They contain a mix of amino acid types and varied primary sequences. Their shapes support many functions, including enzymes, cellular messengers, and molecular transporters. These roles often need the proteins to stay soluble in the...

intrinsically disordered proteins

Flexible Protein Regions and Binding

Intrinsically disordered proteins are proteins that do not fold into one fixed three-dimensional shape. Their flexible structure helps them work with ordered proteins to do jobs that rigid proteins cannot easily do. They are found more often in eukaryotes than in prokaryotes, and they can be fully disordered or made of both ordered and disordered regions. This lack of a rigid shape is linked to amino acid makeup. These proteins usually have many polar and charged amino acids and fewer...

protein complex assembly

How Proteins Self-Assemble in Cells

Proteins can self-assemble into working complexes inside cells. Some complexes are homomeric, which means they contain more than one copy of the same protein. Others are heteromeric, which means they are built from different protein types. Most protein complexes form through ordered self-assembly. In some cases, assembly factors help guide the proteins into the correct structure. Even in the crowded space inside a cell, proteins usually find the right partners and form functional complexes. <br...

conjugated proteins

Conjugated Proteins and Their Roles

Conjugated proteins are proteins that bond with a non-protein part. Unlike simple proteins, which contain only amino acids, these protein complexes include another chemical moiety attached covalently. That extra part can change how the protein works in the body. Nucleoproteins are conjugated proteins that contain nucleic acids. They are grouped as deoxyribonucleoproteins (DNPs) or ribonucleoproteins (RNPs). A nucleosome is a common DNP example, where nuclear DNA is associated with histone...

amyloid fibrils

Amyloid Fibrils in Brain Disease

Amyloid fibrils are clumps of misfolded proteins linked to brain disease and other disorders. In normal cells, misfolded proteins are usually refolded by chaperone proteins or broken down by the proteasome. But in some mutations or diseases, these proteins can build up into large clusters and then assemble into long fibers called fibrils. Amyloid deposits were seen as early as 1639 in the liver and spleen. In 1854, Rudolph Virchow used iodine staining, a method normally used to identify...

antibody structure

Antibodies are built from heavy and light chains that work together to form a Y-shaped molecule. These chains give the antibody its basic structure and help it bind to specific targets. The two upper arms of the Y contain the variable regions, which differ from one antibody to another. These variable regions help determine which antigen, or foreign molecule, the antibody can recognize. The lower part of the antibody is the constant region. This region is more similar across antibodies and...

protein families

Protein Families and Superfamilies

Protein families are groups of homologous proteins with similar amino acid sequences and three-dimensional shapes. They often appear after gene duplication, when an extra copy of a gene is added to an organism’s genome. Mutations can then change the amino acids, as long as the protein can still be made correctly. If the new proteins keep similar amino acids in key places, their domains and overall three-dimensional structure can stay similar too. Members of the same family can share as little...

key terms and concepts

Explore how antibody heavy and light chains form a Y-shaped molecule, with variable regions for target binding and a constant region that helps define class.

Antibody Heavy and Light Chains | JoVE K12

molecular biology

JoVE Core 分子生物学通过清晰简洁的动画视频课程展示了细胞的分子过程。此外，在科学家在行动的视频中，这些概念的应用是通过现代实验室中的真实实验演示的。

Arizona Science Standards

Life Science

HS+B.L1

HS+B.L1U1.5

myJoVE Corporation

Characteristics of Life

Biology is a natural science that studies life and living organisms, including their structure, function, development, interactions, evolution, ...

https://cloudfront.jove.com/files/media/science-education/science-education-thumbs/10647.jpg

Levels of Organization

Biological organization is the classification of biological structures, ranging from atoms at the bottom of the hierarchy to the Earth&#x27;s biosphere. ...

the-tree-of-life-bacteria-archaea-and-eukaryotes

The Tree of Life - Bacteria, Archaea, and Eukaryotes

Prokaryotic Cells

Prokaryotes are small unicellular organisms that include the domains &#8212; Archaea and Bacteria. Bacteria include many common microorganisms, such as ...

Introduction to Virus

Viruses are unique biological entities that blur the boundary between living and non-living systems. Although they lack cellular structure and metabolic ...

Size and Structure of Viral Genomes

Viral genomes exhibit remarkable diversity in size, structure, and composition, influencing their replication strategies and interactions with host cells. ...

Compare and contrast existing models, identify patterns, and use structural and functional evidence to analyze the characteristics of life. Engage in argument about the designation of viruses as non-living based on these characteristics.
EXPLANATION: Students begin to develop patterns of living and non-living organisms in kindergarten and build on detailed characteristics of different classifications of living organisms throughout elementary and middle school. Biology 1 discussions introduce viral particles and viral cycles, building on student understanding of living organisms to engage in an argument regarding the classification of a viral particle as either living or non-living.

BIO1.LS1.1

What are Cells?

Cells are the smallest and basic units of life, whether it is a single cell that forms the entire organism, e.g., in a bacterium, or trillions of them, ...

Eukaryotic Compartmentalization

One of the distinguishing features of eukaryotic cells is that they contain membrane-bound organelles, such as the nucleus and mitochondria, that carry ...

Eukaryotic Evolution

The endosymbiont theory is the most widely accepted theory of eukaryotic evolution; however, its progression is still somewhat debated. According to the ...

Animal and Plant Cell Structure

Animal and plant cells not only differ in their structure, function, and mode of nutrition but also in how they reproduce, specialize, and organize into ...

Evaluate comparative models of various cell types with a focus on organic molecules that make up cellular structures.
EXPLANATION: Students explicitly discuss the structure and function of major cellular organelles in seventh grade. Building on this understanding, Biology I students should shift their focus to the different types of cells found in organisms and how the role of each cell type relates to its composition and the prevalence of different organelles within that cell. An example might include the absence (or enucleation) of the nucleus in red blood cells in mammals providing for increased levels of oxygen transport in organisms or the lack of centrioles in most neurons. Varying cell types can include both prokaryotic and eukaryotic cell types.

BIO1.LS1.2

Nucleic Acids

Nucleic acids are the most important macromolecules for the continuity of life. They carry the cell&#39;s genetic blueprint and carry instructions for its ...

The DNA Helix

Deoxyribonucleic acid, or DNA, is the genetic material responsible for passing traits from generation to generation in all organisms and most viruses. DNA ...

DNA Base Pairing

Erwin Chargaff&#x2019;s rules on DNA equivalence paved the way for the discovery of base pairing in DNA. Chargaff&#x2019;s rules state that in a ...

The Central Dogma

The central dogma explains the flow of genetic information from DNA nucleotides to the amino acid sequence of proteins.
RNA is the Missing Link Between ...

DNA Packaging

Overview

Eukaryotes have large genomes compared to prokaryotes. In order to fit their genomes into a cell, eukaryotes must pack their DNA tightly inside ...

Organization of Genes

Overview

The genomes of eukaryotes can be structured in several functional categories. A strand of DNA is comprised of genes and intergenic regions. ...

Karyotyping

Describing the number and physical features of chromosomes can reveal abnormalities that underlie genetic diseases. This description is facilitated by ...

Replication in Prokaryotes

Overview

DNA replication has three main steps: initiation, elongation, and termination. Replication in prokaryotes begins when initiator proteins bind to ...

Replication in Eukaryotes

Overview

In eukaryotic cells, DNA replication is highly conserved and tightly regulated. Multiple linear chromosomes must be duplicated with high ...

Mutations

Overview

Mutations are changes in the sequence of DNA. These changes can occur spontaneously or they can be induced by exposure to environmental factors. ...

Transcription

Overview
Transcription is the process of synthesizing RNA from a DNA sequence by RNA polymerase. It is the first step in producing a protein from a gene ...

Translation

Lesson: Translation
Translation is the process of synthesizing proteins from the genetic information carried by messenger RNA (mRNA). Following ...

RNA Structure

Overview
The basic structure of RNA consists of a five-carbon sugar and one of four nitrogenous bases. Although most RNA is single-stranded, it can form ...

RNA Stability

Intact DNA strands can be found in fossils, while scientists sometimes struggle to keep RNA intact under laboratory conditions. The structural variations ...

pre-mRNA Processing

In eukaryotic cells, transcripts made by RNA polymerase are modified and processed before exiting the nucleus. Unprocessed RNA is called precursor mRNA or ...

Types of RNA

Overview
Three main types of RNA are involved in protein synthesis: messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA). These RNAs ...

MicroRNAs

siRNA - Small Interfering RNAs

Small interfering RNAs, or siRNAs, are short regulatory RNA molecules that can silence genes post-transcriptionally, as well as the transcriptional ...

piRNA - Piwi-interacting RNAs

PIWI-interacting RNAs, or piRNAs, are the most abundant short non-coding RNAs. More than 20,000 genes have been found in humans that code for piRNAs while ...

CRISPR and crRNAs

Bacteria and archaea are susceptible to viral infections just like eukaryotes; therefore, they have developed a unique adaptive immune system to protect ...

lncRNA - Long Non-coding RNAs

In humans, more than 80% of the genome gets transcribed. However, only around 2% of the genome codes for proteins. The remaining part produces non-coding ...

What are Proteins?

Protein Organization

Protein Folding

Protein Families

Protein families are groups of homologous proteins; that is, they have similarities in amino acid sequences and three-dimensional structures. Protein ...

Conservation of Protein Domains Over Different Proteins

Protein domains are small structurally independent units that are part of a single amino acid chain.&#160; Although these domains are often structurally ...

Globular and Fibrous Proteins

Many proteins can be classified into two distinct subtypes - globular or fibrous. These two types differ in their shapes and solubilities.
Globular ...

Intrinsically Disordered Proteins

Intrinsically disordered proteins are a group of proteins that do not fold into specific three-dimensional structures. Their structural flexibility allows ...

Protein Complex Assembly

Proteins can form homomeric complexes with another unit of the same protein or heteromeric complexes with different types.&#160; Most protein complexes ...

Conjugated Proteins

Simple proteins and protein complexes contain only amino acids. In contrast, many other proteins, called conjugated proteins, covalently bond with ...

Allosteric Proteins-ATCase

Binding sites linkages can regulate a protein&#39;s function.&#160; For example, enzyme activity is often regulated through a feedback mechanism where the ...

Amyloid Fibrils

Amyloid fibrils are aggregates of misfolded proteins.&#160; Under most circumstances, misfolded proteins are either refolded by chaperone proteins or ...

Cooperative Allosteric Transitions

Cooperative allosteric transitions can occur in multimeric proteins, where each subunit of the protein has its own ligand-binding site. When a ligand ...

Phosphorylation

Ligand Binding Sites

Proteins are dynamic macromolecules that carry out a wide variety of essential processes; however, the activities of most proteins depend on their ...

Protein Kinases and Phosphatases

Proteins undergo chemical modifications that trigger changes in the charge, structure, and conformation of the proteins. Phosphorylation, acetylation, ...

Protein-protein Interfaces

Many proteins form complexes to carry out their functions, making protein-protein interactions (PPIs) essential for an organism&#39;s survival. Most PPIs ...

GTPases and their Regulation

Guanine nucleotide-binding proteins (G-proteins), also known as GTPases, are a superfamily of proteins that regulate many cellular processes, such as cell ...

Conserved Binding Sites

Many proteins&#8217; biological role depends on their interactions with their ligands, small molecules that bind to specific locations on the protein ...

Covalently Linked Protein Regulators

Proteins can undergo many types of post-translational modifications, often in response to changes in their environment. These modifications play an ...

the-equilibrium-binding-constant-and-binding-strength

The Equilibrium Binding Constant and Binding Strength

The equilibrium binding constant (Kb) quantifies the strength of a protein-ligand interaction. Kb can be calculated as follows when the reaction is at ...

protein-complexes-with-interchangeable-parts

Protein Complexes with Interchangeable Parts

Groups of proteins may form a complex where each protein in this complex has a different role in the overall execution of the complex&#8217;s function. ...

Cofactors and Coenzymes

Mechanical Protein Functions

Proteins perform many mechanical functions in a cell. These proteins can be classified into two general categories- proteins that generate mechanical ...

Allosteric Regulation

Structural Protein Function

Structural proteins are a category of proteins responsible for functions ranging from cell shape and movement to providing support to major structures ...

Ligand Binding and Linkage

Allosteric proteins have more than one ligand binding site; the binding of a ligand to any of these sites influences the binding of ligands to the other ...

Protein Networks

An organism can have thousands of different proteins, and these proteins must cooperate to ensure the health of an organism. Proteins bind to other ...

Integrate evidence to develop a structural model of a DNA molecule. Using the model, develop and communicate an explanation for how DNA serves as a template for self-replication and encodes biological information.
EXPLANATION: Discussions of DNA in earlier grades have been limited to discussions of genes and the role of genes in the appearance and activities of an organism. Biology 1 represents a student's introduction to a molecular model of a DNA as well as the organization of DNA into genes and genes subsequently into chromosomes. Students should address interactions between genes in proteins which regulate both the shape and reproduction of DNA molecules. It is important to note that not all segments of DNA are transcribed for proteins. Portions of DNA are involved in regulating the expression of genes or affect the structure of the chromosomes (replication origin, centromeres, and telomeres).

What is the Cell Cycle?

The cell cycle refers to the sequence of events occurring throughout a typical cell&#8217;s life. In eukaryotic cells, the somatic cell cycle has two ...

Interphase

The cell cycle occurs over approximately 24 hours (in a typical human cell) and in two distinct stages: interphase, which includes three phases of the ...

The Cell Cycle Control System

Positive Regulator Molecules

Inhibition of CDK Activity

S-Cdk Initiates DNA Replication

M-Cdk Drives Transition Into Mitosis

Mitogens and the Cell Cycle

Replicative Cell Senescence

Abnormal Proliferation

cells-coordinate-growth-and-proliferation

Cells Coordinate Growth and Proliferation

Create a model for the major events of the eukaryotic cell cycle, including mitosis. Compare and contrast the rates of cell division in various eukaryotic cell types in multicellular organisms.
EXPLANATION: Students first discuss mitosis in seventh grade, specifically focusing on the role of mitosis in creating genetically identical daughter cells. Biology 1 discussions should connect a student's understanding of gene expression and protein function with the process of mitosis to explore the differentiation of cell types from otherwise identical daughter cells. Discussions should also include varying rates of mitotic division and the relationship between these rates of division and the function of specific cell types within eukaryotic organisms. Examples may include the extremely limited use of mitosis by neurons due to their interconnectedness within neural networks or the rapid rates of mitosis with growing root tips.

BIO1.LS1.6

Antibody Heavy and Light Chains

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