protien structure

what are the elements found in a protien

CHON(s)

main bonding of a secondary structure is ___?

hydrogen bonding

Specifically, hydrogen bonds form between:

• The C=O (carbonyl oxygen) of one amino acid

• The N–H (amide hydrogen) of another amino acid

stablize alpha helix and beta pleated sheets

definition of globular protien

soluble protiens with hydrophobic groups pointing inwards

Explain how hydrophobic interactions contribute to the structure of a protein?

cause nonpolar amino acid side chains to cluster in the interior of the protein, away from water. This helps the protein fold into a stable three-dimensional (tertiary) structure.

explain the role of chaperonins?

help folding - specialized proteins shaped like barrels that provide an ideal environment for folding.

diseases of misfolding protein?

misfolding protein nullifies that proteins funtion causing

diseases like alzehiemers and parkinson

what is the primary structure of protein structure

sequence of amino acids linked by peptide bonds just a polypeptide chain

this sequence determines how protein will fold and function

what is the secondary structure of protein structure

local folding of the polypeptide chain into α-helices and β-pleated sheets, stabilized by hydrogen bonds between the backbone amino acids.

what is the tertiary structure of protein structure

overall 3d shape of single polypeptide chain, formed when secondary structures fold due to interactions between amino acid side chains.

R group interactions: hydrophobic, ionic, disulfide, Van der Waals, hydrogen bonds determine functional shape

what is the quaternary structure of protein structure

Quaternary structure is two or more polypeptide chains that join together to form a functional protein.

Multiple subunits held together by the same types of interactions found in tertiary structure.

what are amyloids

clumps(aggregates) of misfolded protiens

explain parralel and anti paralel beta sheets?

Parallel and antiparallel β-sheets are types of secondary protein structure formed when β-strands are held together by hydrogen bonds.

Parallel β-sheet

• Adjacent β-strands run in the same direction (N-terminus → C-terminus).

• Hydrogen bonds are slightly angled, making them a bit less stable.

give a protein example of primary protein stucture

insulin - basic amino acid sequence

give an protein example of a secondary protein stucture

keratin specifically has alpha helix

this structure makes hair strong

give an protein example of a tertiary protein stucture

myoglobin its job is to store oxygen

it needs a globular shape to make a pocket to store oxygen

give an example of a qauternary protein structure

hemoglobin needs 4 protein chains to coperate to carry oxygen in blood

A protein contains several folded regions: Hydrophobic amino acids are clustered in the center while polar amino acids are on the outside.

a) What level of protein structure is shown?
b) Why are hydrophobic amino acids located in the center?
c) How does this arrangement help the protein function?

a.) tertiary

b.) avoid water so they cluster together in the middle

c) makes a stable 3d shape

A protein is composed of four separate polypeptide chains:Each circle represents a folded polypeptide.

a) What level of protein structure is shown?
b) Name a protein that has this structure.
c) What is the advantage of having multiple subunits?

a.) qauternary

b.) hemoglobin

c.) subunits can cooperate together

The diagram below shows a protein before and after heating:a) Which level(s) of structure are affected by heating?
b) What is this process called?
c) How would the protein's function change?

a.) tertiary ,secondary, qaurtenary has weak interactions these break due to heating only primary structure remains unchanged due to strong peptide bonds

b.) denaturation

c.) it will not be able to carry outs its function

how can a change of an amino acid in the primary structure of a protein affect the tertiary structure and function of protein?

Yes, the protein’s function can change because the amino acid substitution alters interactions such as hydrogen bonds, ionic bonds, and hydrophobic interactions. This can change the folding of the tertiary structure, including the active site or binding pocket, so the protein may no longer bind to its target molecule.

difference between denaturation and mutation

Denaturation is loss of protein shape due to environmental conditions without changing the amino acid sequence, whereas mutation is a change in the amino acid sequence due to a change in DNA.

how does denaturation affect protein

Denaturation

What it is:

Loss of protein shape due to environmental conditions

Causes:

• Heat

• pH change

• Salts / chemicals

What changes?

Secondary, tertiary, (and quaternary) structures

Primary structure stays the same

Why it happens:

Weak bonds break (hydrogen, ionic, hydrophobic interactions)

Effect:

Protein unfolds → active site changes → loss of function

how does mutation affect a protein

What it is:

Change in the DNA sequence

Cause:

• DNA replication errors

• Mutagens (radiation, chemicals)

What changes?

• Primary structure (amino acid sequence)

Why it happens:

• Codon changes → different amino acid inserted

Effect:

• May change folding → may or may not affect function

Key idea:
👉 Different amino acid sequence → possible new shape

A protein contains the following amino acid sequence:

Valine – Leucine – Isoleucine – Phenylalanine

A mutation changes Leucine to Lysine.

Question:
Explain why this mutation might significantly affect the tertiary structure of the protein.

This mutation may significantly affect the tertiary structure because leucine is a non-polar, hydrophobic amino acid, whereas lysine is positively charged and hydrophilic. The substitution changes the chemical properties of the R group and may disrupt hydrophobic interactions that help stabilize the protein's folded structure. As a result, the protein may fold differently, altering its tertiary structure and potentially affecting its function.

(*when asked for specific amino acid consider hydrophobic and hydrophillic how this affects shape*)

explain the function of collegen, opsin ,and fibrin?

collogen -Provides strength and support to connective tissues such as skin, tendons, ligaments, cartilage, and bones.

opsin - helps with vision

fibrin - forms blood clots to prevent blood loss