Amino Acids, Peptide Bonds, and Protein Structure

Which level of protein structure is determined by the sequence of amino acids?

Primary structure. The primary structure of a protein is simply the sequence of amino acids held together by peptide bonds.

Secondary Structure of Proteins

Shape (helix/pleated) that forms when hydrogen bonds are added between carboxyl and amino groups.

Protein

is a biologically functional molecule made up of one or more polypeptides, each folded and coiled into a specific three-dimensional structure

ionic bond

Formed when one or more electrons are transferred from one atom to another

double bond

A chemical bond formed when atoms share two pairs of electrons

essential elements

A chemical element required for an organism to survive, grow, and reproduce. Of the 92 natural elements, about 20-25% are essential elements. Humans need 25 essential elements, whereas plants only need 17.

polar covalent bond

A covalent bond in which electrons are not shared equally

Electronegativity

A measure of the ability of an atom in a chemical compound to attract electrons

Polypeptide

A polymer (chain) of many amino acids linked together by peptide bonds.

Compound

A substance made up of atoms of two or more different elements joined by chemical bonds

hydrophobic interactions

A type of weak chemical bond formed between two nonpolar amino acids

What makes up hydrogen bonds?

-OH and NH -tip: OH look it's a Northern Hemisphere/Southern Hemisphere Polar Bear! -OH, NH, SH at the end of the R group makes it a Polar amino acid.

What 3 groups make up an amino acid?

Amino (NH3+), Carboxyl (COO-), Central Alpha Carbon (Ca), and Hydrogen

Non-polar amino acids will have what at the end of the R group?

CH (carbon and hydrogen)

chaperones

Help fold proteins

which force is most influential in determining the secondary structure of a protein?

Hydrogen bonding -The secondary structure of a protein is built by hydrogen bonds between the carboxyl groups and amino groups on the back bones of the amino acids.

What type of bonds occur in secondary structure of protein synthesis?

Hydrogen bonds

degradation

The breaking apart of the primary structure/peptide bonds by hydrolysis

Quaternary structure

The fourth level of protein structure; the shape resulting from the association of two or more polypeptide subunits. -more than one amino acid/polypeptide/protein, held together by R groups/side chains. Not all proteins need this structure.

covalent bond

The sharing of a pair of valence electrons by two atoms.

What to Hydrophobic amino acids always end with?

a carbon

nonpolar covalent bond

a covalent bond in which the electrons are shared equally by the two atoms

denatured protein

a protein whose structure has been changed by physical or chemical agents

polar uncharged

are hydrophilic. Side chains consist of special groups such as OH, NH2, SH, Polar amino acids contain oxygen or nitrogen or both, in addition to carbon and hydrogen in their R group.

peptide bond

bond formed between amino acids

Amino Acids

building blocks of proteins-is an organic molecule with both an amino group and a carboxyl group. -the general formula: at the center of the amino acid is an asymmetric carbon atom called the alpha carbon. Its four different partners are an amino group, a carboxyl group, a hydrogen atom, and a variable group symbolized by R. The R group, also called the side chain, differs with each amino acid.

polar charged amino acids

contain oxygen or nitrogen, or both, in addition to carbon and hydrogen in their R group.

Denature

environmental change that causes the protein to misfold or unfold by breaking side chain bonds/secondary structure, but does NOT break the primary structure

non polar amino acids

hydrophobic amino acids contain only carbon or hydrogen or both, in the R group. Polar amino acids contain oxygen or nitrogen, or both, in addition to carbon and hydrogen in their R group.

what type of protein bond if broken tends to aggregate?

hydrophobic interactions (non polar)

What are the four levels of protein Structure?

primary, secondary, tertiary, quaternary

tertiary structure of protein

protein structure is formed when the twists and folds of the secondary structure fold again to from a larger 3D structure. -the result of different secondary structures interacting with one another via their R groups/side chains -these interactions include hydrophobic interactions, hydrogen bonds, ionic bonds, and disulfide bonds. -proteins can now function at this stage.

conformation

refers to a proteins 3D structure or the active protein

confirmational stability

refers to all the forces that keep a protein properly folded in its active form.

primary structure of protein

sequence of amino acids by peptide bonds, -The Carboxyl group and amino group of two amino acids bond together by using 2 hydrogens and one H2O. through a process called dehydration reaction. A water molecule is lost in this process. Amino group + Carboxyl group

Chemical bonds are

the redistribution of electrons between atoms, leading to a more stable configuration

Molecule

two or more atoms held together by covalent bonds

hydrogen bond

weak attraction between a hydrogen atom and another atom