Name: peptide bond formation and shape
Uploaded: 2020-09-24T15:06:53.000Z
Duration: 2 min 43 s
Channel: JoVE

K12 Standards

Pennsylvania State Academic Standards

9-12

Life Science

matter-and-energy-in-organisms-and-ecosystems

Matter and Energy in Organisms and Ecosystems

3.1.9-12.F

Peptide Bonds

Los aminoácidos se unen covalentemente entre sí a través de enlaces peptídicos. Un enlace peptídico une el grupo carboxilo de un aminoácido al grupo amino del otro. Los péptidos son pequeñas cadenas de aminoácidos que varían de dos a cincuenta monómeros.Un enlace peptídico se forma a través de una reacción de condensación que libera una molécula de agua. Cuando un grupo amino y un grupo carboxilo se unen, resulta en la formación de un grupo amida. El enlace peptídico tiene una estructura plana rígida y muestra algunas características de un enlace doble.Esto se debe a que el enlace doble en el carbonilo puede actuar como una estructura de resonancia con el enlace peptídico carbono-nitrógeno. Esta resonancia conduce a la disminución de la longitud del enlace simple, a un aumento de la longitud del enlace doble e inhibe la rotación de los grupos alrededor del enlace peptídico. Los enlaces peptídicos pueden existir en conformaciones cis y trans.En la conformación cis, los carbonos alfa están en el mismo lado del enlace peptídico, y en la conformación trans, están en lados opuestos del enlace. Los enlaces peptídicos ocurren principalmente en la conformación trans, excepto cuando la prolina contribuye con su grupo amino a la formación de enlaces. Los aminoácidos unidos a través de enlaces peptídicos tienen un N-terminal y un C-terminal.El N-terminal es el extremo donde el grupo amino no participa en la formación de un enlace peptídico, y el C-terminal es el extremo donde el grupo carboxilo no participa en la formación de un enlace peptídico. La secuencia de aminoácidos en un péptido o proteína siempre comienza con el N-terminal y termina con el C-terminal. Cuando dos aminoácidos se unen a través de un enlace peptídico, se conocen como dipéptidos.Cuando tres y cuatro aminoácidos se unen a través de enlaces peptídicos, se conocen como tripéptidos y tetrapéptidos, respectivamente. Y cuando varios aminoácidos se unen mediante enlaces peptídicos, se les conoce como polipéptidos. Los enlaces peptídicos se pueden romper rápidamente mediante hidrólisis utilizando catalizadores químicos, como ácidos o enzimas conocidas como proteasas.La ruptura de los enlaces peptídicos implica la adición de una molécula de agua. Alternativamente, estos enlaces pueden romperse espontáneamente mediante un proceso lento en presencia de agua.

los enlaces peptídicos

Un enlace peptídico une covalentemente los aminoácidos a través de una reacción de deshidratación. El grupo carboxilo de un aminoácido y el grupo amino de otro aminoácido se combinan, liberando una molécula de agua. El enlace resultante es el enlace peptídico. Los productos que forman estos enlaces son péptidos. A medida que más aminoácidos se unen a esta cadena en crecimiento, la cadena resultante es un polipéptido. Cada polipéptido tiene un grupo amino libre en un extremo. Este extremo tiene el terminal-N, o el aminoterminal, y el otro extremo tiene un grupo carboxilo libre—el terminal-C o carboxilo. Mientras que los términos polipéptido y proteína se utilizan a veces indistintamente, un polipéptido es técnicamente un polímero de aminoácidos, mientras que el término proteína se utiliza para un polipéptido o polipéptidos que se han combinado y a menudo han unido grupos protésicos no peptídicos, tienen una forma distinta, y una función única.
 Química de los enlaces peptídicos
 Un enlace peptídico tiene una estructura plana rígida debido a la resonancia. Esta resonancia implica el compartir de electrones entre los enlaces dobles presentes en el grupo carbonilo y el enlace péptido entre el carbono y el nitrógeno, que es un enlace sencillo. Esto resulta en el aumento de la longitud del enlace doble y en la disminución de la longitud del enlace sencillo con respecto a la longitud esperada en ausencia de resonancia.
 Los enlaces peptídicos pueden ocurrir en dos posibles configuraciones: cis y trans. En la configuración cis, los carbonos alfa de ambos aminoácidos conectados por el enlace peptídico están en el mismo lado del enlace; y en la configuración trans, los carbonos alfa de los dos aminoácidos conectados por el enlace peptídico están en lados opuestos del enlace. La configuración cis ocurre generalmente cuando la prolina contribuye con su grupo amino a la formación del enlace; sin embargo, sólo alrededor del 10% de las prolinas están precedidas por enlaces cis.
 La rotación no es posible alrededor de los enlaces peptídicos debido a su estructura rígida. Sin embargo, la rotación puede ocurrir alrededor de los enlaces que unen el carbono alfa a los átomos de nitrógeno y carbono, respectivamente.
 Este texto ha sido adaptado de<a href="https://openstax.org/books/biology-2e/pages/3-4-proteins"> Openstax, Biología 2e, Capítulo 3.4: Proteínas</a>.

Los Enlaces Peptídicos

Un enlace peptídico se une covalentemente a los aminoácidos a través de una reacción de deshidratación. El grupo carboxilo de un aminoácido y el aminoácido de otro aminoácido ...

Education

Educación

JoVE Core

Chemistry

Química

Biochemistry

Bioquímica

KEY TERMS AND CONCEPTS

TÉRMINOS Y CONCEPTOS CLAVE

peptide bond formation and shape

Peptide bonds join amino acids into peptides and polypeptides. They form when the carboxyl group of one amino acid reacts with the amino group of another. This dehydration reaction releases a water molecule and creates a covalent link.

As more amino acids are added, the chain becomes a polypeptide. Each polypeptide has a free amino group at one end. This end is the N-terminal, or amino-terminal. The other end has a free carboxyl group. This end is the C-terminal, or carboxyl-terminal.

The terms polypeptide and protein are sometimes used as if they mean the same thing. Technically, a polypeptide is a polymer of amino acids. A protein is a polypeptide, or more than one polypeptide, that has joined together and often carries non-peptide prosthetic groups. Proteins also have a distinct shape and a unique function.

Peptide bonds have a rigid, planar shape because of resonance. Resonance is the sharing of electrons between the carbonyl group and the peptide bond between carbon and nitrogen. This changes bond lengths. The double bond becomes longer, and the single bond becomes shorter than expected without resonance.

Peptide bonds can exist in cis and trans forms. In the cis form, the alpha carbons of the two amino acids are on the same side of the bond. In the trans form, they are on opposite sides. The cis form usually appears when proline donates its amino group, but only about 10% of prolines are preceded by cis bonds.

Rotation does not occur around the peptide bond because of its rigid structure. Rotation can still happen around the bonds that connect the alpha carbon to the nitrogen and carbon atoms. This limited movement helps define the shape of peptides and proteins.

Peptide Bond Formation and Shape

functional groups

Functional Groups in Organic Chemistry

Functional groups in organic chemistry are groups of atoms that give molecules specific properties. When these groups attach to a carbon skeleton, they can change how the molecule behaves. Some functional groups make a molecule hydrophilic, or water-attracting. Others make it hydrophobic, or water-repelling. Functional groups are a key part of organic chemistry and are also found in major biological molecules. They appear in carbohydrates, proteins, lipids, and nucleic acids. Each functional...

structure of lipids

Lipids, Fats, and Cell Membranes

Lipids are nonpolar molecules that do not mix well with water. They are hydrophobic, which means “water fearing,” because they contain mostly nonpolar carbon-carbon and carbon-hydrogen bonds. In cells, lipids store long-term energy as fats, help insulate plants and animals, and form protective water-repellent layers on feathers and fur. They are also part of cell membranes and serve as building blocks for many hormones. Common lipids include fats, oils, waxes, phospholipids, and steroids. A...

chemistry of the cell

Cell Chemistry: Water and Macromolecules

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chemistry of carbohydrates

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protein and protein structure

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amino acids

Amino Acids and Protein Building

Amino acids are the building blocks of proteins. Each amino acid has the same basic structure. A central carbon atom, called the alpha carbon, is bonded to an amino group, a carboxyl group, and a hydrogen atom. Each amino acid also has an R group, or side chain, attached to the central carbon. The R group is different for every amino acid. It helps determine whether an amino acid is acidic, basic, polar, or nonpolar. Scientists call these molecules amino acids because they contain both amino...

peptide bonds

Peptide bonds join amino acids into peptides and polypeptides. They form when the carboxyl group of one amino acid reacts with the amino group of another. This dehydration reaction releases a water molecule and creates a covalent link. As more amino acids are added, the chain becomes a polypeptide. Each polypeptide has a free amino group at one end. This end is the N-terminal, or amino-terminal. The other end has a free carboxyl group. This end is the C-terminal, or carboxyl-terminal. The...

nucleic acids

DNA and RNA: Genetic Instructions

DNA and RNA are the nucleic acids that store genetic information and help direct cell activity. These macromolecules carry the cell’s genetic blueprint and the instructions it uses to function. DNA is the genetic material in all living organisms, from single-celled bacteria to multicellular mammals. In eukaryotic cells, DNA is found in the nucleus and also in organelles such as chloroplasts and mitochondria. In prokaryotes, DNA is not enclosed in a membrane. The full genetic content of a cell...

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from dna to protein

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polymers

Polymer Chains and How They Form

Polymers are long chains of molecules made from repeating units called monomers. The word polymer comes from the Greek words "poly," meaning many, and "mer," meaning parts. Polymers can be found in nature, such as DNA and proteins, or made synthetically, such as plastics. A polymer’s shape helps define its properties. Some polymers form linear chains, while others are branched or arranged in complex networks. Functional groups on a polymer also affect how it behaves. The repeating units in a...

key terms and concepts

Learn how peptide bonds form amino acid chains, create N- and C-terminals, and why resonance gives peptides a rigid cis and trans structure.

Peptide Bond Formation and Shape | JoVE K12

chemistry

JoVE Core Química da vida a los conceptos de química general mediante lecciones de vídeo basadas en animaciones, concisas y fáciles de entender. Además, en los vídeos de científicos en acción, se muestran experimentos de investigación clásicos y originales realizados en laboratorios de todo el mundo.

Louisiana Student Standards for Science

High School

Life Sciences

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

From Molecules To Organisms: Structures And Processes

HS-LS1-6

Next Generation Science Standards

From Molecules to Organisms: Structures and Processes

Florida Department of Education

SC.912.L.18

SC.912.L.18.1

SC.912.L.18.4

new-york-state-science-learning-standards

New York State Science Learning Standards

HS-LS1-6.

Light as Energy

The energy required to carry out photosynthesis is light&#8212; typically electromagnetic radiation from the sun. The range of all possible wavelengths is ...

What is Photosynthesis?

All living organisms on Earth are directly or indirectly dependent on photosynthesis. It is the only biological process that can capture energy from ...

The Anatomy of Chloroplasts

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Photosystems

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The Photochemical Reaction Center

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The Antenna Complex

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the-z-scheme-of-electron-transport-in-photosynthesis

The Z-Scheme of Electron Transport in Photosynthesis

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The Calvin Benson Cycle

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Photosynthesis

Autotrophs

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Plant Pigment Chromatography and Floating Leaf Discs in a Vacuum
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Plant Pigment Chromatography
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3.1.9-12.E

Compounds Essential to Human Function

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Introduction to Carbohydrates

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Sugars as Energy Storage Molecules

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lipid-derived-compounds-in-the-human-body

Lipid-derived Compounds in the Human Body

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What are Proteins?

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Globular Proteins

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Fibrous Proteins

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Protein Denaturation

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Role of Proteins in the Human Body

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Amino acids

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A peptide bond covalently attaches amino acids through a dehydration reaction. One amino acid&#39;s carboxyl group and another amino acid&#39;s amino ...

Nucleic Acids and Nucleotides

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Nucleic Acid Structure

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What is Energy?

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Energy Budgets and Reproductive Strategies

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Energy Dynamics

The Food Chain
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Production Efficiency

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Trophic Efficiency

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Introduction to Cellular Respiration

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What is Glycolysis?

Overview
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Energy-requiring Steps of Glycolysis

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Energy-releasing Steps of Glycolysis

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Outcomes of Glycolysis

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Pyruvate Oxidation

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Mitochondria

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Mitochondrial Membranes

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The Inner Mitochondrial Membrane

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The Citric Acid Cycle: Overview

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The Citric Acid Cycle: Output

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electron-transport-chain-complex-i-and-ii

Electron Transport Chain: Complex I and II

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electron-transport-chain-complex-iii-and-iv

Electron Transport Chain: Complex III and IV

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The Electron Transport Chain

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the-supercomplexes-in-the-crista-membrane

The Supercomplexes in the Crista Membrane

The mitochondrial cristae membrane is the primary site for the oxidative phosphorylation (OXPHOS) process of energy conversion mediated through ...

ATP Synthase: Structure

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ATP Synthase: Mechanism

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The ADP/ATP Carrier Protein

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Students who demonstrate understanding can use a model to illustrate that cellular respiration is a chemical process whereby the bonds of food molecules and oxygen molecules are broken and the bonds in new compounds are formed resulting in a net transfer of energy.  Assessment Boundary: Assessment should not include identification of the steps or specific processes involved in cellular respiration.

3.1.9-12.G

What is an Ecosystem?

Overview

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Trophic Levels

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Primary Production

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The Water Cycle

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The Carbon Cycle

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The Nitrogen Cycle

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The Phosphorus Cycle

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The Sulfur Cycle

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Students who demonstrate understanding can use mathematical representations to support claims for the cycling of matter and flow of energy among organisms in an ecosystem.  Assessment Boundary: Assessment is limited to proportional reasoning to describe the cycling of matter and flow of energy.

3.1.9-12.H

Peptide Bond Formation and Shape

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