Lecture 6- What Are Proteins? Flashcards
How many different proteins do we make in a typical cell?
< 21, 000 (about 10,000)
Cell specific genes
make proteins that allow cells to take on its specific shape and perform its function
housekeeping genes
make glycolysis enzymes and other proteins needed by both cells
The average human protein is 450 aa in size
How big is our largest protein?
34 000 a.a
What are different ways we can draw a protein?
a. Primary structure
b. Space filling
c. Wire model
d. Ribbon model- useful to look at tertiary and secondary structure
Different shapes of proteins
a. Globular- compact, most are soluble
b. Membrane- cylindrical, most have hydrophobic around middle
c. Fibrous- long and thin; most are bundled into huge filaments
Protein domains
What is a domain?
Portions of proteins that can fold, function, and evolve independently of each other
What regulates the genes?
Transcription Factor Proteins
Gene
region of DNA needed to produce RNA
Binding site for transcription factors
regulate the gene
Promoter
Where the RNA polymerase first binds the gene
Kinase
enzyme that make/ break covalent bond
How can proteins be regulated?
- Some proteins are regulated by phosphates (attachment of phosphate= on = shape change)
- Some proteins are regulated by nucleotides (GDP-off, GTP-on)
- Some proteins are regulated by activator or inhibitor proteins
What are four levels of protein structure?
Primary
Secondary
Tertiary
Quaternary
What are 8 general functions of proteins
- catalyze covalent bond breakage
-provide mechanical support to cells and tissues
-carry small molecules or ions
-generate movement in cells and tissues
-store amino acids or ions
-carry extracellular signals from cell to cell
-detect signals and transmit them to the cell’s response machinery
-bind to DNA to switch genes on or off
