Protein Purification

Hydrophobic Amino Acids

Amino acids that are nonpolar and do not form hydrogen bonds with water.

Function of Hydrophobic Amino Acids

Create a stable core that maintains a protein's shape.

Folding of Hydrophobic Amino Acids

These amino acids should be on the inside of the folded protein structure.

Hydrophilic Amino Acids

Amino acids with polar side chains that can form hydrogen bonds with water.

Function of Hydrophilic Amino Acids

Help proteins stay dissolved and interact with other molecules.

Folding of Hydrophilic Amino Acids

These amino acids should face outward in the folded protein.

Basic Amino Acids

Amino acids that carry a positive charge and are hydrophilic.

Interaction of Basic Amino Acids

Form ionic bonds with acidic amino acids.

Folding of Basic Amino Acids

Usually located on the outside of the protein.

Acidic Amino Acids

Amino acids that carry a negative charge and are hydrophilic.

Function of Acidic Amino Acids

Help stabilize proteins and interact well with water.

Folding of Acidic Amino Acids

These should be placed on the outside, near basic side chains.

Cysteine Amino Acids

Contain sulfur and can form covalent disulfide bonds.

Disulfide Bonds

Bonds that lock parts of a protein together, providing strength.

Folding of Cysteine Amino Acids

Cysteines should be positioned to come close together.

Overall Protein Folding Concept

Proteins fold based on the desire of side chains for their preferred environments.

Hydrophobic Behavior in Folding

Hydrophobic side chains tend to hide inside the protein structure.

Role of Hydrophilic Side Chains

Hydrophilic, basic, and acidic side chains face outward to interact with water.

Function of Cysteines in Folding

Cysteines stabilize the structure by forming disulfide bonds.

Comparison of Protein Folding

Folding a protein can be compared to folding a rope or noodle into a tight bundle.

Properties of Hydrophobic Amino Acids

Made mostly of carbon and hydrogen, making them nonpolar.

Effect of Water on Hydrophobic Amino Acids

Water pushes them away, causing them to group together.

Group of Amino Acids That Are Comfortable in Water

Hydrophilic amino acids.

Characteristics of Basic Amino Acids

They are positively charged and interact well with water.

Importance of Basic Amino Acids

Stabilize structure and bind negatively charged molecules like DNA.

Characteristic of Acidic Amino Acids

They easily interact with water and carry a negative charge.

Interaction of Acidic with Basic Amino Acids

Form ionic bonds that help in protein stability.

Role of Sulfur in Cysteine Amino Acids

Allows for special bonding creating disulfide bonds.

What do disulfide bonds do?

Act like staples locking proteins' parts together.

Where should you place hydrophobic amino acids?

They should be buried in the center of the protein.

Where should you place hydrophilic amino acids?

They should be exposed on the outside of the protein.

What do hydrophobic amino acids create in proteins?

A stable core that helps maintain the protein’s shape.

What happens to proteins without hydrophobic amino acids?

They would not fold correctly.

Arrangement of Basic Amino Acids during Folding

Place them near acidic side chains.

Key Idea about Disulfide Bonds in Proteins

Add strength and long-term stability to protein structures.

Location of Acidic Amino Acids during Folding

Should be located on the outside of the protein structure.

Define Hydrophobic Amino Acids' nature

Nonpolar and avoiding interactions with water.

Define Hydrophilic Amino Acids' nature

Polar and promoting interactions with water.

Why is the positioning of basic amino acids important?

To stabilize interactions with negatively charged molecules.

What analogy is used to describe protein folding?

Comparing it to folding a rope or noodle.

What drives the folding of proteins?

The preference of different side chains for various environments.

Consequences of Protein Misfolding

It can lead to malfunction and disease.

What kind of bonds stabilize the structure of proteins?

Disulfide bonds and ionic bonds among others.

What are the two characteristics of Cysteine?

Contains sulfur and can form disulfide bonds.

What do the hydrophobic pieces in a noodle analogy represent?

The hydrophobic amino acids that group together inward.

What happens to hydrophobic amino acids in aqueous environments?

They tend to group together, away from water.

What is a crucial aspect of protein folding?

That different side chains have different preferences for their environment.

How do the environments influence amino acid placement?

Hydrophobic amino acids hide inside, while hydrophilic ones are exposed.

What structural role do hydrophilic amino acids play in proteins?

They help proteins remain dissolved and interact with other molecules.