1.3 - INTRODUCTION TO MOLECULAR BIOLOGY Flashcards
(31 cards)
✓ All newly synthesized proteins need to fold up correctly (3-D shape)
* Native conformation
* Non-native (e.g., unfolded or misfolded)
* Essential for enzymatic activity or structural roles in the cell
Post-translational modifications
(PTMs)
stabilize partially folded
regions in their correct form
Chaperone proteins
Proteins fold in the
ER
✓ Amino acids of some proteins need to be chemically modified
* Addition of phosphate groups
* Phosphorylation can determine protein function
Post-translational modifications
(PTMs)
increase the functional diversity of the proteome by the covalent addition of functional groups, proteolytic cleavage of regulatory subunits, or degradation of entire proteins
Post-translational modifications (PTMs)
PTMs include ?; influence almost all aspects of normal cell biology and pathogenesis
phosphorylation, methylation and acetylation
Identifying and understanding PTMs is critical in the study of ?
cell biology and disease treatment and prevention
most common mechanism of regulating protein function and transmitting signals throughout the cell. Protein phosphorylation (e.g., serine, threonine, or tyrosine residue) is one of the most important and well-studied PTMs.
Phosphorylation
refers to addition of a methyl group to lysine (K) or arginine (R) residue of a protein. Methylation is mediated by methyltransferases and S-adenosyl methionine (SAM) is the primary methyl group donor
Methylation
refers to the addition of acetyl group in a protein. It is catalyzed by histone acetyltransferase (HAT) that transfer the acetyl moiety from acetyl-CoA to the amino group of lysine (K) residue
Acetylation
Conformation of a Protein
Primary
Secondary
Tertiary
Quaternary
amino acid sequence in a polypeptide chain
Primary
loops, coils, barrels, helices, sheets, or other shapes formed by hydrogen bonds between neighboring carboxyl and amino groups
Secondary
three-dimensional forms shaped by bonds between R groups, interactions between R groups and water
Tertiary
protein complexes formed by bonds between separate polypeptides
Quaternary
Proteins must fold into ? to function
1 or more specific shape(s) or conformation(s)
The 3-D conformation determines a
protein’s function
Folding occurs because of
attractions and repulsions between atoms
Some amino acids are attracted to water
hydrophilic
Repelled water
hydrophobic
Misfolded Protein in Alzheimer
Amyloid beta precursor protein
Alzheimer OMIM
104760
Misfolded Protein Sclerosis
Superoxide dismutase
Sclerosis OMIM
147450
