PROTEINS

Multiple Choice

Amino acid is a compound which has at least one

• A. Amino group and one amide group

• B. Amino group and one hydroxyl group

• C. Amino group and one carboxyl group

• D. Hydroxyl group and one carbonyl group

​20 amino acids. *zwitterions at physiological pH [+ and - charge]

10 nonpolar/hydrophobic aa. 10 polar/hydrophillic aa

the -carboxyl group -COOH

pH of 9​

​C-TERMINUS

the +amino group +NH3

pH of 2​

• Lysine Lys K {primary amine reacts w/cis retinal}

​n-terminus

​*ALL 19 ARE S CONFIGURATION EXCEPT FOR CYSTEINE [THIOL HAS HIGH PRIORITY= R CONFIGUR.]

​Researchers hope to design a polypeptide inhibitor to a site with the repeated sequence A-Q-E-K-K. Which of these inhibitor sequences is most likely to succeed?

​

A-S- K -D- E

​

NP, P, ​ACIDIC, BASIC, BASIC

ALANINE , GLUTAMINE, GLUTAMATE, LYSINE, LYSINE

NP, P, BASIC, ACIDIC, ACIDIC​

ALANINE, SERINE, LYSINE, ASPARTATE, GLUTAMATE​

Multiple Choice

What is the monomer of Proteins?

• Nucleotides

• Amino Acid

• Fatty Acids

• Monosaccharides

Multiple Choice

Amino acids all have the same general structure except for the:

• Amino Group

• Carboxyl Group

• 'R' Group

• Carbonyl Group

Multiple Choice

How many natural amino acids are found

• 10

• 9

• 20

• 21

• GLYINE IS THE ONLY ACHIRAL AMINO ACID​

• 10 HYDROPHOBIC AA

• PROLINE IS THE MOST STERICALLY STRAINED *2 STRUCTURE

​

​

​Some text here about the topic of discussion.

NONPOLAR [HYDROPHOBIC]

AMINO ACIDS​

​

​GLY G, ALA A, VAL V, CYS C, PRO P, LEU L, IIE I , MET M, TRP W, PHE F ARE THE 10 NONPOLAR AA

Multiple Choice

If a methyl group (-CH₃), which does not like water, were at the 'R', the amino acid would likely be:

• Hydrophobic

• Hydrophilic

• Ionic

• Acidic

3 BASIC POLAR

• HAL

• HISTIDINE​ HIS H

• ARGININE ARG R

• LYSINE LYS K ​

• PROTON ACCEPTORS, N+ CAN ACCEPT A H+ TO BECOME POSITIVE

​SER S, THR T, TYR Y, ASN N, GLN Q, LYS K, ARG R, HIS H, ASP D, GLU E ARE THE 10 POLAR AMINO ACIDS

​POLAR [HYDROPHILLIC AMINO ACIDS]

​the carbonyl is the electrophile [accepts e-]

the nitrogen is the nucleophile ​[donates e-]

new bond formed between nitrogen & carbon =amide​

Multiple Choice

The bond that joins amino acids are called:

• Peptide Bonds
• Ester Bonds
• Glycosidic Linkages
• Phosphodiester Bonds

• ​Water is used to break peptide bonds

• Two amino acids are formed with its N & C TERMINUS

​PROTEIN STRUCTURE:

PRIMARY 1, SECONDARY 2, TERTIARY 3, QUATERNARY 4​

​PRIMARY [PEPTIDE BONDS]

SECONDARY [HYDROGEN BONDING, BACKBONE]

• ALPHA & BETA HELICES

• ALPHA = MORE STABLE DUE TO H+ BOND

  PARALLEL STRANDS = SAME DIRECTION

• ANTIPARALLE​L = C-N OTHER N-C

TERTIARY [SIDE CHAIN INTERACTIONS]

QUATERNARY ​*PHOSPHORYLATION, DISULFIDE BONDS, GLYCOSYLATION, UBIQUITINATION

​PHOSPHORYLATION

• SERINE SER S

• THREONINE THR T

• TYROSINE TYR Y​

​POST TRANSLATIONAL MODIFICATIONS

​FORMATION OF DISULFIDE BONDS BETWEEN CYSTEINE [THIOL GROUP S-H] ---> S-S

​GLYCOSYLATION : SHORT CARBOHYDRATE POLYMERS ARE LINKED TO PROTEINS

​UBIQUITINATION : UBIQUITIN MARKS THE PROTEIN FOR DEGRADATION

• ATTACHED TO THE SUBSTRATE ​

• 3 STEP PROCESS E1, E2, E3,

• UACTIVATE, UCONJUGATE, UPROTEIN LIGASE

​TERTIARY PROTEIN STUCTURE

​PROTEIN FOLDING & DENATURING

MUST KNOW...​

• THE SOLVATION ENVIRONMENT INFLUENCE THE WAY A PROTEIN FOLDS ON A POLYPEPTIDE ​CHAIN

• HIGH OR LOW PH

• TEMPERTURE

• HIGH SALT CONCENTRATIONS [EX, UREA]​

*CHAPERONES HELP FOLD DENATURED PROTEINS BACK TO THEIR NATIVE STATE