Proteins and Corresponding Clinical Correlations - L1 NYIT

Question 1

D-/L-Amino Acids

Answer 1

mirror image conformations of the amino acids, mammalian proteins are composed of L-amino acids

Question 2

peptide bond

Answer 2

is between the carboxyl of one amino acid and the amino group of the adjacent amino acid

Question 3

deleterious mutation

Answer 3

a mutation that dramatically alters the comformation of a protein by changing the amino acid and properties

Question 4

nitrogen balance

Answer 4

protein measurement, different balances include positive, negative and balanced.

it has to do with how much is eaten versus excreted

Positive: intaking much more than loss/excretion

Negative: intake is much less than loss/excretion

Balance: intake is about the same as what is excreted.

Question 5

essential amino acids

Answer 5

PVT TIM HALL
phe, val, thr, try, ile, met, his, arg, leu, lys

essential because they tend to be branched or aromatic, our bodies cannot synthesize those conformations

Question 6

conditional essential amino acids

Answer 6

His - it’s plentiful but still cant be synthesized by the human body. There is no dietary need for it.

Arg - essential for growing children, adults get sufficient amounts from the urea cycle and gut.

Question 7

nonessential amino acids

Answer 7

mostly made out of glycolytic or CAC intermediates with an addition of an amino group

Cys is made from essential AA Met

Phe is usd to make Tyr (in PKU patients Tyr is essential)

Question 8

pKa

Answer 8

low pKa means stronger acid, high pKa means weaker acid

disassociation constant

Question 9

primary structure

Answer 9

the linear sequence of AA in the protein/peptide

ways to determine sequence: edman degradation, mass spec - both followed by either chromatography or electrophoresis. Also, sequencing of genome or mRNA

primary structure often determines secondary, tertiary and quaternary structures

Question 10

secondary structure

Answer 10

local/short range folding, original folding of a protein. Into beta sheets or alpha helices. somewhat determined by H-bonding btwn the backbone/exterior of the chain - aim to maximize H-bonding but to miminize steric hinderance

bends with Pro or Gly are usually exterior and unprotected making them susceptible to proteolysis

Question 11

tertiary structure

Answer 11

The folding of peptide domains into biologically functional, and final, arrangements.

formation of globular protein shapes, stabalized by H-bonds, electrostatic interactions and disulfide bonds

in aq soln (like interstitial fluid or blood) outside tends to be polar and inside np. For transmembrane proteins the outer surface is lined with np AA

Question 12

quaternary structure

Answer 12

formation of multisubunit proteins, you see interactions between the subunits. common example is hemoglobin, made of 4 subunits

Question 13

motif and domains

Answer 13

motif - a combination of secondary structure elements (Helix, sheet, bend) that produces specific patterns with associated properties.

ex motif - helix-turn-helix

Domains can be built of motifs, these are fundamental 3D units of peptides. homologous - different proteins from different organisms sharing a common domain that perfoms a similar function

Question 14

chaperons

Answer 14

proteins that correct and guide the folding of proteins that need help folding, called heat shock proteins

Question 15

protein modifications

Answer 15

phosphorylation - serine, threonine, tryosine

methylation - lysine, arginine

acetylation - lysine, arginine

hydroxylation - lysine, proline (collagen)

ubiquitination - lysine

glycosylation - O-linked (ser, thr, tyr) and N-linked (asn, arg)

Question 16

protein conformational disorders

Answer 16

groups of diseases which are altered protein conformations that cause toxicity and functional deficiency.

these include alzheimer’s disease, huntington disease, parkinson disease
(by amyloids) and TSEs - Prions

Question 17

kwashiorkor

Answer 17

Negative N balance

• protein def, enough carbs
• edema due to def albumin, muscle wasting due to lack of essential AA, anemia, stunted growth, skin lesions, depigmented hair, anorexia and enlarged fatty liver

Question 18

marasmus

Answer 18

Negative N balance

• def in calorie and proteins
• other symptoms: arested growth, extreme muscle wasting and loss of subcutaneous fat, weakness and anemia

NO EDEMA

Question 19

Serine, threonine and tyrosine have what special features?

Answer 19

They have hydroxyl groups that can form hydrogen bonds, accept phosphate groups or accept fatty acids and form esters

Question 20

what two amino acids have carboxylate sides chains that bind Ca2+

Answer 20

aspartate and glutamate

Question 21

histidine is an imidazole, what can it bind?

Answer 21

The imidazole nitrogen can bind copper and iron