Bonding in proteins.

https://www.youtube.com/watch?v=bjGsDpLyr2g

Where do the bonds in proteins form

Between the R groups of the amino acids on a polypeptide chain , type of bonding depends on the specific amino acids present in the polypeptide.

Where is hydrogen bonding found

R group containing hydroxyl, due to slight positive and negative charges present on hydroxyl, a hydrogen bond can form between these two R groups, this contributes to the 3d shape of a polypeptide chain

Hydrogen bonds are weak bonds, easily broken by high temp or pH changes.

What are hydrophobic interactions

Several amino acids have uncharged R groups, they are called non polar amino acids, these amino acids are not attracted to water so they are hydrophobic

Amino acids with hydrophobic R groups tend to cluster together so they can exclude water molecules (hydrophobic interactions), which tend to be found in centre of proteins

What are hydrophillic interactions

Hydrophillic amino acids tend to be found on the surface of proteins, where they can interact with water molecules.

hydrophobicv and hydrophillic interactions have weak bonds

What are ionic bonds

These are found between amino acids with charged R groups

One amino acid has pos charge R group, one has neg charge R group

These opp charges attract each other and form an ionic bond, this bond holds together different parts of the polypeptide chain together.

Ionic bonds are broken by changes in pH

What does R group of cysteine have

Contains sulfur atom, sulfur atoms in the two cysteine molecules can form a covalent bond, this is called a disulfide bond

They are relatively strong bonds ,

What happens if these bonds form between amino acids on same polypeptide chain

Involved in tertiary structure

What happens if these bonds form between amino acids on different subunits

Theyre also involved in quat structure