Name: how amino acid sequence shapes proteins
Uploaded: 2023-04-30T10:34:15.000Z
Duration: 1 min 25 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 Folding

새로 합성된 펩타이드에서 구성 아미노산 간의 상호 작용은 종종 기능적 형태인 네이티브 형태(native conformation)라고 하는 안정적인 3차원 구조로 접히도록 안내합니다.
첫째, 선형 폴리펩티드 사슬은 아미노산 잔기 사이의 수소 결합을 통해 알파 나선과 베타 시트로 접힙니다.
나선 또는 베타 시트에서 튀어나온 소수성 측쇄가 함께 모여 주변의 물 분자를 제거합니다. 결과적으로, 폴리펩티드는 소수성 코어(hydrophobic core)가 있는 느슨하게 접힌 중간체로 포장됩니다.
표면의 극성 잔류물은 추가적인 수소 결합과 이온 상호 작용을 만드는 반면, 인접한 시스테인은 공유 이황화 결합을 형성하여 단백질을 원래 형태로 안정화합니다.
여러 시스테인이 있는 단백질의 경우, 단백질 이황화 이소머라제 효소는 티올 그룹의 빠른 교환을 촉매하여 올바른 이황화 결합 형성을 가능하게 합니다.
대부분의 단백질은 스스로 접히지 않으며 열 충격 단백질과 샤페로닌의 도움을 받습니다.
이러한 분자 샤페론은 풀린 펩타이드를 결합하고 응집을 방지하거나 펩타이드가 본래의 형태로 접힐 수 있는 미세환경을 제공하여 접힘 과정을 가속화합니다.

<ol>
	<li>Lodish, Harvey, et al. 분자 세포 생물학. 8판. WH Freeman and Company, 2016. 피 81-85</li>
	<li>Donald Voet 및 Judith G Voet 생화학. 4판. JOHN WILEY & SONS, INC. 2011. 278-290</li>쪽
	<li>Nelson and Cox, Lehninger, Principles Of Biochemistry, 7판. WH Freeman and Company, 2016년. 피 396-407</li>
</ol>

단백질 접기

단백질은 펩타이드 결합으로 서로 연결된 아미노산 사슬입니다. 합성 시 단백질은 생물학적 기능에 중요한 3차원 구조로 접힙니다. 구성 아미노산 간의 상호 작용은 단백질 접힘을 유도하므로 단백질 구조는 주로 아미노산 서열에 따라 달라집니다.

단백질 구조는 생물학적 기능에 매우 중요합니다

단백질은 화학 반응 촉매, 면역학적 방어, 저장, 수송, 세포 통신, 이동 및 구조적 지원과 같은 광범위한 생물학적 기능을 수행합니다. 단백질의 기능은 주로 자물쇠와 열쇠와 유사하게 다른 분자를 인식하고 결합하는 데 달려 있습니다. 따라서 각 단백질의 구체적인 활동은 독특한 3차원 구조에 따라 달라집니다.

단백질이 기능을 하기 위해서는 정확하게 접혀야 합니다. 대부분의 단백질은 가장 안정하고 생물학적으로 활성인 구조로 접혀지기 전에 여러 중간 형태를 거칩니다. 단백질의 잘못된 접힘은 세포의 전반적인 기능을 손상시킬 수 있습니다. 인간에게 잘못 접히거나 펼쳐진 단백질이 축적되면 낭포성 섬유증, 알츠하이머병, 파킨슨병, 근위축성 측색 경화증 및 크로이츠펠트-야콥병이 발생합니다.

단백질 구조의 중요한 결정 요인

단백질은 폴리펩티드라고 불리는 하나 이상의 아미노산 사슬로 구성됩니다. 폴리펩티드는 스스로 빠르게 접혀 3차원 구조를 형성하는 선형 사슬로 합성됩니다. 폴리펩티드와 단백질이라는 용어는 때때로 같은 의미로 사용되지만 가장 일반적으로 생물학적 기능을 수행할 수 있는 접힌 폴리펩티드를 단백질이라고 합니다. 단백질 구조는 일반적으로 1차, 2차, 3차, 4차의 네 가지 수준으로 설명됩니다. 대부분의 폴리펩티드는 혈액 내 산소 운반 단백질인 헤모글로빈과 같이 전체적으로 조밀하고 구형의 3차 구조로 접혀 있습니다. 케라틴과 같은 일부 단백질은 긴 섬유질을 형성하며 머리카락과 손톱에서 흔히 발견됩니다. 구형 단백질은 섬유질 단백질과 달리 물에 용해됩니다.

폴리펩티드 사슬의 아미노산 서열은 그 구조의 주요 결정 요인입니다. 아미노산 서열은 2차 구조의 유형과 위치를 결정합니다. 또한, 단백질의 전반적인 3차 구조는 아미노산을 서로 구별하는 독특한 화학 그룹인 아미노산 측쇄 사이의 화학적 결합에 의해 주로 안정화됩니다. 이러한 측쇄는 전하(양 또는 음)를 띠거나 극성-비전하 또는 비극성을 띠고 있습니다.

아미노산은 측쇄 그룹에 따라 독특한 물리적, 화학적 특성을 가지고 있습니다. 예를 들어, 극성 및 하전된 아미노산은 물과 상호작용하여 수소 결합을 형성하며 이를 친수성이라고 합니다. 대조적으로, 비극성 아미노산은 물과의 상호작용을 피하므로 소수성이라고 불립니다. 따라서 단백질이 세포 환경에서 접힐 때 소수성 아미노산의 측쇄는 수성 환경에서 멀리 떨어진 단백질 코어에 묻혀 있습니다. 대조적으로, 친수성 아미노산 측쇄는 단백질 표면에 노출됩니다.

단백질 코어에 단단히 채워진 소수성 아미노산은 측쇄 그룹 사이에 약한 반 데르 발스 상호 작용을 형성합니다. 이러한 반 데르 발스 힘은 접힌 단백질에 추가적인 안정성을 부여합니다. 단백질 표면에 노출된 극성 아미노산은 물 분자나 다른 극성 아미노산 측쇄와 자유롭게 수소 결합을 형성합니다. 양전하와 음전하를 띤 아미노산은 단백질 외부에도 존재하며, 근처의 반대 전하를 띤 아미노산과 이온 결합을 형성합니다.

아미노산 시스테인에 있는 두 개의 설프하이드릴 또는 SH 그룹 사이에 이황화 결합이 형성됩니다. 이는 접힌 단백질을 강화하는 것처럼 작용하는 강력한 상호작용입니다. 이황화 결합은 접힌 단백질을 가장 선호하는 3차원 형태로 고정시킵니다. 단백질의 적절한 접힘은 또한 pH, 염분 농도, 온도 등과 같은 세포 환경의 다른 요인에 따라 달라집니다. 단백질 환경에서 물리적, 화학적 조건의 변화는 단백질을 함께 유지하는 화학적 상호 작용에 영향을 미치고 단백질이 잘못 접히는 원인이 될 수 있습니다. 또는 단백질 변성으로 알려진 과정인 생물학적 기능이 전개되어 상실됩니다.

단백질은 펩타이드 결합으로 서로 연결된 아미노산 사슬입니다. 합성시 단백질은 3 차원 형태로 접히며 ...

Education

교육

JoVE Core

Cell Biology

세포생물학

Unit 1

제1단원

Protein Structure

단백질 구조

KEY TERMS AND CONCEPTS

주요 용어 및 개념

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 by binding to another molecule, much like a lock and key. That is why its specific three-dimensional shape is so important.

To be functional, a protein must fold correctly. Many proteins pass through several intermediate forms before reaching the most stable and biologically active shape. When proteins misfold, they can disrupt cell function. In humans, misfolded or unfolded proteins are linked with cystic fibrosis, Alzheimer’s disease, Parkinson’s disease, amyotrophic lateral sclerosis, and Creutzfeldt-Jakob disease.

Proteins are made of one or more amino acid chains called polypeptides. A polypeptide starts as a linear chain and then folds quickly into a three-dimensional structure. The words polypeptide and protein are sometimes used interchangeably, but a folded polypeptide that can do a job is usually called a protein. Protein structure is often described at four levels: primary, secondary, tertiary, and quaternary.

Most polypeptides fold into a compact, globular tertiary structure. Hemoglobin, the oxygen-carrying protein in blood, is an example. Some proteins, such as keratins, form long fibers and are found in hair and nails. Globular proteins are usually soluble in water, while fibrous proteins are not.

The amino acid sequence is the main factor that determines protein shape. It helps decide where secondary structures form and how the full tertiary structure develops. Side chains, the chemical groups that make amino acids different from one another, stabilize the folded protein. These side chains may be charged, polar but uncharged, or non-polar.

Polar and charged amino acids interact with water and are called hydrophilic. Non-polar amino acids avoid water and are called hydrophobic. When a protein folds in a cell, hydrophobic side chains are usually buried in the core, away from water, while hydrophilic side chains stay on the surface. Tight packing in the hydrophobic core creates weak Van der Waals interactions that help stabilize the structure.

Hydrophilic side chains on the outside can form hydrogen bonds with water or with other polar side chains. Positively and negatively charged amino acids can also form ionic bonds with nearby oppositely charged amino acids. Another strong bond, called a disulfide bond, forms between two sulfhydryl, or SH, groups on cysteine. This bond helps lock the protein into its most stable three-dimensional shape.

Protein folding also depends on the cell’s environment. pH, salt concentration, and temperature can affect the chemical interactions that hold a protein together. If these conditions change, a protein may misfold or unfold and lose its function. This process is called protein denaturation.

How Amino Acid Sequence Shapes Proteins

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...

protein organization

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...

protein folding

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

Learn how amino acid sequence, side-chain interactions, and cell conditions shape protein structure, stability, and function in high school biology.

How Amino Acid Sequence Shapes Proteins | 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.

new-york-state-science-learning-standards

New York State Science Learning Standards

Structure and Function

HS-LS1-1.

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

Cell Structure

Background
Cells represent the most basic biological units of all organisms, whether it be simple, single-celled organisms like bacteria, or large, ...

Visualizing Onion and Cheek Cells
ExpandImmediately before the experiment, wash and peel onion bulbs for the class.
Remove the entire brown outer skin and ...

Visualizing Onion and Human Cells
ExpandIn this experiment you will prepare different types of cells from a plant and animal, onion and human ...

What are Cells?

Cell Diversity

The concept of a cell started with microscopic observations of dead cork tissue by Robert Hooke in 1665. Hooke coined the term &#34;cell&#34; based on the ...

Cytoplasm

The cytoplasm consists of organelles and a framework of protein scaffolds called the cytoskeleton suspended in an aqueous solution, the cytosol. The ...

The Nucleus

The nucleus is a membrane-bound organelle that acts as a control center in a eukaryotic cell. It contains chromosomal DNA, which controls gene expression ...

The Central Dogma

The DNA Helix

Nucleic Acids

DNA as a Genetic Template

Structure of a Gene

A gene is the fundamental unit of heredity. Every individual has two copies of each gene, one inherited from each parent. Although most people contain the ...

Chromosome Structure

Base-pairing and DNA Repair

What is Gene Expression?

A gene is a stretch of DNA that serves as the blueprint for functional RNAs and proteins. Since DNA is comprised&#160; of nucleotides and proteins are ...

RNA Structure

The basic structure of RNA consists of a string of ribonucleotides attached by phosphodiester bonds. Although most RNA is single-stranded, it can form ...

Protein Families

Types of RNA

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

Conservation of Protein Domains

Transcription

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

Globular and Fibrous Proteins

Translation

Translation is the process of synthesizing proteins from the genetic information carried by messenger RNA (mRNA). Following transcription, it constitutes ...

Intrinsically Disordered Proteins

Ribosomes

Ribosomes translate genetic information encoded by messenger RNA (mRNA) into proteins. Both prokaryotic and eukaryotic cells have ribosomes. Cells that ...

Protein Complex Assembly

Protein and Protein Structures

Conjugated Proteins

Proteins: From Genes to Degradation

Amyloid Fibrils

What are Proteins?

Proteins are polymers of amino acids linked together by peptide bonds. Proteins and polypeptides are interchangeably used to refer to long chains of amino ...

Ligand Binding Sites

Protein Organization

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

Protein-Protein Interfaces

Proteins are chains of amino acids linked together by peptide bonds. Upon synthesis, a protein folds into a three-dimensional conformation, critical to ...

Conserved Binding Sites

Cofactors and Coenzymes

Enzymes are proteins made of amino acids. The functional group of each constituent amino acid catalyzes a wide variety of chemical reactions via ionic ...

Cooperative Allosteric Transitions

Protein Kinases and Phosphatases

GTPases and their Regulation

Covalently Linked Protein Regulators

protein-complexes-with-interchangeable-parts

Protein Complexes with Interchangeable Parts

Mechanical Protein Function

Structural Protein Function

Protein Networks

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.]

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. ...

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 ...

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

Structural Organization of the Human Body: An Overview

It is convenient to consider the body&#39;s structures in terms of fundamental levels of organization that increase in complexity: subatomic particles, ...

Overview of Human Digestion

The human body contains a monogastric digestive system. In a monogastric digestive system, the stomach only contains one chamber in which it digests food. ...

Anatomy of the Intestines

Although digestion of proteins, carbohydrates, and lipids may begin in the stomach, it is completed in the intestine. The absorption of nutrients, water, ...

Accessory Organs

Accessory organs are those that participate in the digestion of food but do not come into direct contact with it like the mouth, stomach, or intestine do. ...

Lipid Digestion

Lipids are large molecules that are generally not water-soluble. Since most of the digestive enzymes in the human body are water-based, there are specific ...

Protein Digestion

Protein digestion begins in the stomach, where the highly acidic environment can easily disrupt protein structure by exposing the peptide bonds of ...

Carbohydrate Digestion

Carbohydrate digestion and metabolism break down simple and complex carbohydrates from food into saccharides (i.e., sugars) for the body to use as energy. ...

What is a Nervous System?

Overview

The nervous system is the collection of specialized cells responsible for maintaining an organism&rsquo;s internal environment and coordinating ...

The Parasympathetic Nervous System

Overview

The parasympathetic nervous system is one of the two major divisions of the autonomic nervous system. This parasympathetic system is responsible ...

The Sympathetic Nervous System

Overview

The sympathetic nervous system&mdash;one of the two major divisions of the autonomic nervous system&mdash;is activated in times of stress. It ...

Oogenesis

In human women, oogenesis produces one mature egg cell or ovum for every precursor cell that enters meiosis. This process differs in two unique ways from ...

What is a Sensory System?

Sensory systems detect stimuli&mdash;such as light and sound waves&mdash;and transduce them into neural signals that can be interpreted by the nervous ...

Fertilization

During fertilization, an egg and sperm cell fuse to create a new diploid structure. In humans, the process occurs once the egg has been released from the ...

What is the Skeletal System?

Overview

The adult human skeleton comprises 206 bones that are connected through cartilage, tendons, and ligaments. The skeleton provides a rigid ...

an-introduction-to-the-zebrafish-danio-rerio

An Introduction to the Zebrafish: Danio rerio

Zebrafish (Danio rerio) are small freshwater fish that are used as model organisms for biomedical research. The many strengths of these fish include their ...

Physiology of the Circulatory System

Homeostasis
Conditions in the external environment of an organism can change rapidly and drastically. To survive, organisms must maintain a fairly ...

Anatomy of the Circulatory System

The human circulatory system consists of blood, blood vessels that carry blood away from the heart, around the body, and back to the heart, and the heart ...

Measuring Blood Pressure
ExpandTo prepare for the blood pressure exercise, simply place the appropriate number of alcohol swabs, sphygmomanometers, and ...

Anatomy of the Heart

The human heart is made up of three layers of tissue that are surrounded by the pericardium, a membrane that protects and confines the heart. The ...

Measuring Circulatory System Function in Humans
ExpandBefore starting the experiment go to the front of the room and collect an alcohol swab, a ...

Blood Flow

Blood is pumped by the heart into the aorta, the largest artery in the body, and then into increasingly smaller arteries, arterioles, and capillaries. The ...

What Are Osmoregulation and Excretion?

Organisms must keep bodily fluids at a constant temperature and pH while maintaining specific solute concentrations in order to support life functions. ...

Blood Withdrawal I

Source: Kay Stewart, RVT, RLATG, CMAR; Valerie A. Schroeder, RVT, RLATG. University of Notre Dame, IN
Blood collection is a common requirement for ...

Kidney Structure

The kidneys are two large bean-shaped organs located in the upper abdomen. They filter the blood several times a day to remove toxins and rebalance water ...

Blood Withdrawal II

Source: Kay Stewart, RVT, RLATG, CMAR; Valerie A. Schroeder, RVT, RLATG. University of Notre Dame, IN
The collection of blood from mice and rats for ...

What is the Immune System?

Overview

The immune system comprises diverse biological structures and processes that protect the body from disease. These processes can be classified ...

Bone Remodeling

Bone remodeling is a continuous and balanced process of bone resorption by osteoclasts and bone formation by osteoblasts. In adults, it helps maintain ...

Spermatogenesis

Spermatogenesis is the process by which haploid sperm cells are produced in the male testes. It starts with stem cells located close to the outer rim of ...

Bone Structure

Within the skeletal system, the structure of a bone, or osseous tissue, can be exemplified in a long bone, like the femur, where there are two types of ...

Breathing

The process of breathing, inhaling and exhaling, involves the coordinated movement of the chest wall, the lungs, and the muscles that move them. Two ...

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

What is Homeostasis?

Maintaining homeostasis requires that the body continuously maintain its internal conditions. Each physiological condition has a particular set point, ...

Negative and Positive Feedback

Homeostatic Imbalance

Homeostasis is the maintenance of a stable internal environment within the body, which is crucial for the proper functioning of cells, tissues, organs, ...

pH Homeostasis

Acid-base homeostasis is essential for maintaining normal physiological activities in humans. The pH of various body fluids is strictly regulated because ...

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

How Amino Acid Sequence Shapes Proteins

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