Exam 2 - Ch 5, 6 + Antibodies (Ch 7) Flashcards
Charge on Arginine at pH 7?
+1
Charge on Aspartic Acid at pH 7?
-1
Charge on Cysteine at pH 7?
0
Charge on Glutamic Acid at pH 7?
-1
Charge on Histidine at pH 7?
0
Charge on Lysine at pH 7?
+1
Charge on Tyrosine at pH 7?
0
pH < pI
What is the net charge on the protein?
Net + charge
pH > pI
What is the net charge on the protein?
Net - charge
1st amino acid the N-terminus or C-terminus?
N-terminus
last amino acid the N-terminus or C-terminus?
C-terminus
What is a conservative mutation?
a mutation that conserves chemical properties (size, polarity, and charge similar for both amino acids)
What is a nonconservative mutation?
a mutation where the properties of the amino acids are different
Explain what affinity chromatography (IMAC, His-tag) is and what its uses are
a separation method based on a specific binding interaction between an immobilized ligand and its binding partner.
High efficiency for removing bulk contaminants, usually 1st step in purification process
Explain IEC (Ion-Exchange Chromatography)
Ion-Exchange Chromatography separates proteins based on charge.
important to match the pH of the buffer with the pI of the protein, and the charge on the resin
often an early step in the purification process
Explain SEC (Size Exclusion Chromatography)
Separates proteins based on their size.
Large protein elutes first, Small protein elutes last.
Size difference needs to be significant (at least a factor of 2).
Which terminus does the arrow point at in a beta-strand?
always C-terminus
What dictates primary structure?
Genes
What is secondary structure? What dictates it?
Alpha helices and beta sheets
Amino Acids dictate
What is tertiary structure?
When secondary structures pack against each other
What is quaternary structure?
multiple protein subunits associated with each other
How can you predict if a protein will fold into an alpha helix based on amino acid sequence?
it will show repeating patterns of side chain polarity every 3-4 amino acids
How can you predict if a protein will fold into a beta sheet based on amino acid sequence?
it will show repeating patterns of side chain polarity every other residue