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