Exam I Flashcards
L designation
The stereoisomer of amino acids that are incorporated into proteins in vivi
In Fischer projection, amine group points LEFT
Zwitterion
Occurs around physiological pH. Carboxyl group is deprotonated and amino group is protonated
pKa amino acid terminals
C -> 2.2
N -> 9.4
L Dopa
A Tyrosine derivative drug with an extra hydroxyl on the ring. Used to treat Parkinson’s
Branched chain AA
Valine
Leucine
Isoleucine
Histidine (His) (H)
Aromatic; pKa of 6; co-ordinates metal ions in hemoglobin
Basic AA
Lysine, Arginine
Helps stabilize the negative phosphate backbones of DNA
Phenylalanine (Phe) (F)
Aromatic; Promotes efficient stacking of protein (especially in cellular membranes)
Glycine (Gly) (G)
Achiral;
Most flexible AA; usually found in tight places and helps avoid steric hindrance
Sulfur Containing AA
Met -> Start codon
Cys –> Tertiary structure ( disulfide bridges); can be disrupted by urea/ethanomercaptol
Alcohol Containing
Involved in phosphorylation reactions; forms phosphate esters
Involved in protein signaling (glycoproteins)
Ser, Thr, Tyr
Proline (Pro) (P)
A pyrollidine heterocyclic;
Forms kinks and tight turns
Found in Elastin (nonhydroxylated)
Found in Fibrous proteins as Hydroxyproline (usually as “x” in Gly-X-Y motif); stabilized triple helix
Found in hairpin loops at the sharp turn (pos 2)
Modified AA
4-hydroxyproline and 5-hydroxyglycine help stabilize protein
Vitamin K
Essential in coagulation cascade; activated by gamma-carboxyglutamate (modified AA)
Deficiency leads to hemmorhaging
Monoasaccharides
Glucose (diabetes/hyperglycemia)
Fructose (fructose accumulation/hypoglycemia)
Galactose (hydrolysis of lactose; mammalian mill synthesis)
Disaccharides
Sucrose (1a, 2b linkage); Glucose + Fructose
Lactose (b 1,4 linkage); Glucose + Galactose
Maltose (a 1,4 linkage); Glucose + Glucose
Other saccharine Containing compounds
Glycoproteins: Oligo + proteins
Glycolipids: Oligo + lipids
Proteoglycan: Glycosaminoglycan + proteins
Sphingolipids
Serine and Palmitic acid derivative
Forms ceramides by attaching sphingosine backbone to amino group
Gaucher Disease
Glucocerebrosidase deficiency
Lysosomal (cellular) accumulation of glucocerebroside in bones, lungs, liver, spleen
Tay-Sachs Disease
Hexominodase deficiency
Build up of GM2 ganglioside
Niaman-Pick Disease
Sphingomyelinase deficiency; cherry spots visible in eye
Build up of sphingomyelin
Alpha Helices
Stabilized by H bonding parallel to helix axis; 3.6 aa/turn
Amphipathic aa are at protein surface; hydrophilic project outwards towards solvent; hydrophobic project onward towards protein core
Beta Sheets
Parallel (same direction wrt terminals); Antiparallel (opposite directions, stronger interactions) ; Mixed (both)
Stabilized by H bonding
Provide bulk of hydrophobic core due to optimal dense packaging
Reverse Turn; Hairpin Loop; Beta Turn
Comprised of 4 amino acids; Proline at pos 2 and Glycine at pos 3
Stabilized by H bonding (carbonyl of aa 1 and amide proton of aa 4)
Rossman Fold (Super-secondary structure)
Several Beta & Beta motifs; A helix connects two parallel Beta sheets
Usually found in glycolysis enzymes
Prions
Contains only proteins; lacks DNA & RNA
Propagates misfolding of proteins
Prion derivative diseases
Infection: Mad Cow Diseass
Genetic Mutation: Creutzfeldt-Jakob disease (CJD)
Tertiary structure
Hydrogen (acid/base)
ionic (salt)
Disulfide (urea/mercaptoethanol)
Hydrophobic interactions (detergent)
Actin fold
Structural domain in G-actin
Region of protein that folds independently; super-secondary structures
Triple Helix
Common for fibrous proteins
Repeat Gly-X-Y motif; X being Proline and Y being lysine (both hydroxylated)
Vitamin C
Required for Proline and Lysine hydroxylation; deficiency leads to inadequate X-Y and leads to scurvy
Ehlers Danlos Syndrome
Mutations in formation of Collagen type I and Collagen type III
Osteogenesis Imperfecta *
Also known as Brittle Bone Disease
Type I Collagen mutation
Elastin
Elastic connective tissue in lungs, arterial walls, etc
Composed of small nonpolar AA (G, V, A) as well as P and K
Alzheimer’s
Accumulation of B Amyloid
Cystic Fibrosis
Deletion of 3 base pairs (phenylalanine at pos 508)
Thick mucus accumulation in lungs
Amyloidosis
Accumulation of amyloid proteins
Primary amyloidosis –> multiple myeloma
Secondary amyloidosis –> Tuberculosis, Chron’s
Diabetes T2 –> Amyllin in pancreas
Dialysis associated amyloidosis –> Accumulation in blood seen in long term
Dialysis patients
Sickle Cell Anemia
B globin
Huntington’s
Poly-Glutamine Repeat
Neurodegenerative
Parkinson’s
Alpha Synuclein
Heat Shock Proteins
Cellular levels are increased during elevated temp in order to reduce protein unfolding
HSP60, HSP70, Chaperones
Utilize ATP
Histones
Alkaline proteins; package DNA into nucleosides and then into dhromatin
Interact with negatively charged phosphate backbones with Lysine + Arginine residues
