Name: how allosteric control changes enzymes
Uploaded: 2020-11-23T11:47:34.000Z
Duration: 1 min 8 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

Allosteric Regulation

다른 자리 입체성 (알로스테릭) 조절은효소 활성 부위를 제외한 뚜렷한 부위를 통해 효소를 조절하는 것을 칭합니다.효소 활성 부위가 아닌 별개의 부위를 통해 효소를 조절하는 것을 칭합니다.분자가 다른 자리 입체성 부위 같은 곳에 결합할 때분자가 다른 자리 입체성 부위 같은 곳에 결합할 때이 결합은 구조적 변화를 유발하거나효소 안의 모양을 바꿉니다.이 같은 행동은기질을 위한 효소 활성 부위의 친화력을 높일 수 있고이는 효소 활동을 촉진 시킵니다.이 과정은 다른 자리 입체성 활성화라 부릅니다.반응 속도인 기질 농도 그래프에서다른 자리 입체성 활성화는양의 S-모양 곡선으로 표현됩니다.효소가 활성화할 때까지 지체 시간이 있는 곳이죠.그다음, 활성 부위의 급상승으로 인해높은 농도의 기질은 결합 할 수 있고반응 속도를 빠른 속도로 높입니다.반면에, 만약 반응기가 효소에 결합하고구조적 변화를 일으키면이는 기질 결합 친화력을 낮춥니다.이 과정을 알로오스테리 억제라 부릅니다.이 경우에는 효소 기능이 감소하고활성화 상태에서 화학 반응 속도가 느려집니다.활성화 상태에서 화학 반응 속도가 느려집니다.

<ol><li>Cornish-Bowden, A. 효소의 알로스테릭 및 협력 상호 작용 이해. FEBS 저널. 281 (2), 621-6332 (2014).</li><li>Tsai, C.-J., Nussinov, R. 생리학적 및 병리학적 맥락에서 EGFR 활성화의 새로운 알로스테릭 메커니즘. 생물물리학 저널. 117 (1), 5-13 (2019).</li></ol>

다른자리입체성 조절

효소의 다른자리입체성 조절(allosteric regulation)은 활성부위(active site)와 다른 위치에 분자가 결합하는 것이 효소 활성에 변화를 일으킬 때 발생합니다. 이러한 유형의 조절은 효소의 활동을 증가시키거나 감소시키는 양성 또는 음성일 수 있습니다. 다른자리입체성(allostery)를 보이는 효소의 대부분은 특정 세포 분자의 분해나 합성에 관여하는 물질대사 효소입니다.
 
 다른자리입체성 억제에서, 다른자리입체성 부위에 분자가 결합하면 기질(substrate)에 대한 효소의 친화력(affinity)을 감소시키는 형태 변화를 일으킵니다. 대개 다른자리입체성 억제제는 효소 또는 효소 경로의 산물이며, 효소 생성물이 효소 자신의 생산을 제한하도록 만듭니다. 이는 되먹임억제(feedback inhibition)의 일종으로 과잉 생성을 방지합니다. 전형적인 예는 이소루신(isoleucine; 아이소루신)으로, 이소루신은 자신의 합성에 중요한 효소의 다른자리입체성 억제제입니다.
 
 반대로, 다른자리입체성 활성제는 기질에 대한 효소의 친화력을 증가시키는 형태 변화를 일으킵니다. 다른자리입체성 활성화는 기질 반응 속도를 크게 증가시키며, 이때 S자 곡선으로 대표되는 반응 속도 증가를 보입니다. 예를 들어 세포 외 리간드(ligand)가 막관통 EGF 수용체(transmembrane EGF receptor)에 결합하면 수용체가 형태 변화를 일으켜 세포 내 인산화효소(kinase) 활동을 활성화합니다. 이때 효소가 여러 개의 단위체(subunit)로 구성된 경우, 다른자리입체성 활성제가 단일 단위체에 결합해 모든 관련 단위체에 대한 친화력을 향상하고 모양 변화를 일으킬 수 있습니다.

효소의 알로스테릭 조절은 활성 부위와 다른 부위에 효과기 분자가 결합할 때 발생합니다.

Education

교육

JoVE Core

Molecular Biology

분자생물학

Unit 1

제1단원

Protein Function

단백질의 기능

KEY TERMS AND CONCEPTS

주요 용어 및 개념

how allosteric control changes enzymes

Allosteric control changes how enzymes work by using a site other than the active site. A small molecule binds to this separate allosteric site and changes the enzyme’s shape. That shape change can alter how well the enzyme binds its substrate and how fast the reaction runs.

Many enzymes use this kind of regulation to turn activity up or down when the cell needs it. In some cases, the allosteric molecule acts as an activator and improves enzyme function. In other cases, it acts as an inhibitor and reduces enzyme function. This control helps cells manage reactions without changing the enzyme’s basic structure.

Allosteric regulation is an important way proteins respond to signals in the cell. It shows how a binding event at one site can affect activity at another site. For high school biology, it is a key example of how protein shape and function are linked.

How Allosteric Control Changes Enzymes

ligand binding sites

How Ligands Attach to Proteins

Ligands attach to proteins at specific binding sites on the protein surface. These sites let proteins interact with other molecules or ions and help them carry out important cell functions. Although many possible ligands may be nearby, only a matching ligand can bind to a given protein. A ligand-binding site has a shape and chemical pattern that fit its ligand. This fit comes from the protein’s amino acid chain, which gives the site its structure and reactivity. The ligand stays in place...

protein-protein interfaces

How Proteins Connect to Form Complexes

Proteins connect with other proteins to form complexes that carry out cell functions. These protein-protein interactions, or PPIs, are important for an organism's survival. Most PPIs are held together by many weak, noncovalent chemical forces rather than one strong bond. The shape of the interaction surface helps determine how two proteins fit together. Many globular proteins have surface shapes that match closely and can form many weak bonds. Other PPIs happen between two helices or between a...

conserved binding sites

Predicting Protein Ligand-Binding Pockets

Protein ligand-binding pockets help explain how proteins work. A ligand is a small molecule that binds to a specific spot on a protein. These sites are often conserved in related proteins because they are important for function. When the exact site on a protein surface is not known, it can be predicted. One approach is the energetic method. It examines how amino acid residues interact with the ligand and looks for positions where the binding energy is lowest. Those low-energy regions are...

the equilibrium binding constant and binding strength

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

Measuring Protein-Ligand Binding Strength

Protein-ligand binding strength can be measured with the equilibrium binding constant, Kb. This value describes how strongly a protein binds a ligand when the reaction has reached equilibrium. In a bound complex, the protein and ligand are joined as PL, while P and L are the unbound forms. Kb can be determined in two main ways. One approach uses equilibrium concentrations. The other uses reaction kinetics, which are the rates of binding and unbinding. Kb can also be related to the binding rate...

cofactors and coenzymes

Protein Helpers: Cofactors and Coenzymes

Cofactors and coenzymes help enzymes work. Many enzymes need these helper molecules to carry out chemical reactions. Without them, the enzyme may not function properly. A cofactor is a helper molecule that can be either an inorganic ion or an organic molecule. Coenzymes are organic cofactors. They often move between enzymes and help transfer chemical groups or electrons during a reaction. Some cofactors are vitamins or come from vitamins. These molecules are important because they support...

allosteric regulation

Allosteric control changes how enzymes work by using a site other than the active site. A small molecule binds to this separate allosteric site and changes the enzyme’s shape. That shape change can alter how well the enzyme binds its substrate and how fast the reaction runs. Many enzymes use this kind of regulation to turn activity up or down when the cell needs it. In some cases, the allosteric molecule acts as an activator and improves enzyme function. In other cases, it acts as an inhibitor...

ligand binding and linkage

Allosteric Proteins: Positive and Negative Effects

Allosteric proteins have more than one ligand binding site. A ligand is a molecule that binds to a protein. When a ligand binds at one site, it can affect binding at the other sites. These sites are called coupled or linked because they influence one another. In enzymes, the site that binds the substrate is the active site. The other site is the regulatory site. When a ligand binds to the regulatory site, it can change the protein’s shape. This conformational change can then alter how the...

cooperative allosteric transitions

Allosteric Switching in Multimeric Proteins

Allosteric switching in multimeric proteins helps explain how ligand binding at one site can change the behavior of the whole protein. In these proteins, each subunit has its own ligand-binding site. When a ligand binds to one subunit, it can cause a shape change that affects the other subunits and their binding sites. This change in shape comes from the protein’s structure, which includes both flexible and stable segments. A molecule that causes the shift is called a modulator. Because the...

phosphorylation

Phosphorylation in Cell Signaling

Phosphorylation is a key step in cell signaling. It changes how a molecule behaves by adding a phosphate group. In many cells, this modification helps control activity, shape, and interactions with other molecules. Phosphorylation is carried out by enzymes called kinases. These enzymes transfer a phosphate group to a target molecule. A phosphatase can remove that phosphate group and reverse the change. Together, kinases and phosphatases help cells turn signals on and off in a controlled way. <br...

protein kinases and phosphatases

Phosphorylation Switches in Protein Control

Protein control often depends on chemical changes that alter a protein’s charge, shape, and conformation. These changes can include phosphorylation, acetylation, glycosylation, nitrosylation, ubiquitination, lipidation, methylation, and proteolysis. In cells, these modifications are usually driven by enzymes. Phosphorylation is one of the most important protein modifications. It adds a phosphate group to a protein and often changes how that protein works. A family of enzymes called kinases...

gtpases and their regulation

GTPase Signaling Switches in Cells

GTPases are cell proteins that act as signaling switches. They help control cell signaling, vesicle transport, cell shape, and cell movement. When these proteins change or stop working properly, disease can result. There are about 40,000 known G-proteins. They are usually grouped into two main types. Small G-proteins have one domain, while large G-proteins have multiple domains. Large G-proteins are also called heterotrimeric G-proteins. They have three subunits: alpha, beta, and gamma. The...

covalently linked protein regulators

How Protein Tags Change Cell Signaling

Proteins can be changed after they are made by adding small chemical tags or small proteins. These post-translational modifications help control protein function and stability when the cell environment changes. Common covalent regulators include methyl, acetyl, and phosphate groups, as well as small proteins such as ubiquitin. About 200 types of covalent regulators have been identified. These tags attach to specific amino acids in a protein. Phosphate groups can attach only to serine,...

protein complexes with interchangeable parts

protein-complexes-with-interchangeable-parts

SCF Ubiquitin Ligase and F-Box Variants

The SCF ubiquitin ligase is a protein complex that uses an F-box protein to help choose which target proteins get marked for destruction. This complex is made of five separate proteins, and each one has a different job. Together, they attach ubiquitin to target proteins so the cell can send those proteins to be degraded. The F-box protein is the part that binds the substrate, or target protein. That binding step lets the ubiquitin-conjugating enzyme reach the target and attach ubiquitin. In...

mechanical protein functions

Protein Force: Cell Movement and Support

Proteins can create and respond to mechanical force in cells. Some proteins generate force, while others are pulled or stretched by it. Proteins such as keratin provide structural support and are subjected to mechanical force. Proteins such as ion pumps help move molecules across cell membranes and can generate mechanical force. Cell movement and muscle contraction depend on turning chemical energy into motion. This often happens through conformational change, which is a shift in a protein’s...

structural protein function

Collagen and the Cell Skeleton

Structural proteins give cells and tissues shape, support, and strength. They help build bones, cartilage, hair, and muscles. Important examples include collagen, actin, myosin, and keratin. Collagen is the most abundant protein in mammals. It is found throughout the body. In skin, ligaments, and tendons, collagen adds tensile strength and elasticity. In bones and teeth, it helps form hard, load-bearing tissue through mineralization. Collagen also does more than provide support. It can...

protein networks

Mapping Protein Interactions

Mapping protein interactions shows how proteins work together in a cell. Many proteins must connect with other proteins to carry out their jobs and keep an organism healthy. These connections can be shown as protein-protein interaction networks, also called protein maps. In these maps, proteins are shown as nodes, or circles. Lines called edges connect two proteins that interact. The network can include stable interactions, such as those in protein complexes, and transient interactions that...

allosteric proteins-atcase

ATCase Feedback Inhibition in Pyrimidine Synthesis

ATCase is a key enzyme in pyrimidine synthesis. It is a cytosolic enzyme that catalyzes the condensation of L-aspartate and carbamoyl phosphate to form N-carbamoyl-L-aspartate. This reaction starts the pathway that makes pyrimidines. ATCase is regulated by feedback inhibition. The end products UTP and CTP bind to the enzyme and reduce its activity when pyrimidine levels are high compared with purines in the cell. This binding at one site affects the linked catalytic site, which helps keep...

key terms and concepts

Learn how allosteric control changes enzyme activity through binding at a separate site, and how activators and inhibitors help cells regulate reactions.

How Allosteric Control Changes Enzymes | JoVE K12

molecular biology

JoVE Core 분자생물학은 명확하고 간결한 애니메이션을 통해 분자 단계에서 일어나는 세포 과정을 설명합니다.또한, 과학자가 직접 실험을 진행하는 실사 영상을 통해 분자생물학 개념의 응용 사례를 보여줍니다.

Arizona Science Standards

Life Science

HS+B.L1

HS+B.L1U1.5

myJoVE Corporation

Characteristics of Life

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

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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

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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

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The Central Dogma

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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

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Karyotyping

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Replication in Prokaryotes

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Replication in Eukaryotes

Overview

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Mutations

Overview

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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
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RNA Structure

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RNA Stability

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pre-mRNA Processing

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Types of RNA

Overview
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MicroRNAs

siRNA - Small Interfering RNAs

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piRNA - Piwi-interacting RNAs

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CRISPR and crRNAs

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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 ...

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Protein Folding

Protein Families

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

Conservation of Protein Domains Over Different Proteins

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Globular and Fibrous Proteins

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Globular ...

Intrinsically Disordered Proteins

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Protein Complex Assembly

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Conjugated Proteins

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Allosteric Proteins-ATCase

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Amyloid Fibrils

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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 ...

Antibody Structure

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

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Conserved Binding Sites

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Covalently Linked Protein Regulators

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The Equilibrium Binding Constant and Binding Strength

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Protein Complexes with Interchangeable Parts

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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).

How Allosteric Control Changes Enzymes

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