1. Structure Flashcards
Squalene (2)
Triterpene (30 Cs) that acts as precursor to cholesterol
Susquiterpenes Carbon Number
15
3 MCFAs
Caproic
Caprylic
Capric
4 LCFAs (+ C#)
Myristic - 14
Palmitic - 16
Stearic - 18
Arachidic - 20
4 Unsaturated Cis FAs (+ description #s)
Palmitoleic - 16:1 (9)
Oleic - 18:1 (9)
Linoleic - 18:2 (9,12)
Linolenic - 18:3 (9,12,15)
2.2 Essential FAs
Linoleic (omega-6) and linolenic (omega-3)
2 Fish Oils
EPA and DHA
Plasmalogens (2)
Glycerophospholipids with C1 ether linkage and an unsaturated tail, named phosphatidal instead of phosphatidyl
Platelet-Activating Factor
Glycerophospholipid with C1 ether linkage to saturated tail, C2 acetyl linkage, and ethanolamine head
Sphingomyelin Structure
Ceramide + Phosphocholine
Cerebroside (2)
Neutral glycosphingolipid consisting of Ceramide + Sugar
2 Acidic Glycosphingolipids
Sulfatides and gangliosides
Maltose
Glucose, glucose alpha-1,4’ linkage
Lactose
Galactose, glucose Beta-1,4’ linkage
Sucrose
Glucose, fructose Alpha-1,Beta-2’ linkage
2 Reducing Sugars
Maltose and lactose
1 Non-Reducing Sugar
Sucrose
Ribose Unique Ring Formation
Pyranose form most stable in solution but furanose form most preferred in nature
Glucan
Polysaccharide of D-glucose monomers
Starch
Mixture of amylose (20-30%) and amylopectin (70-80%) alpha-glucans
Amylose
Alpha-1,4’ glucan
Amylopectin (2)
Alpha-1,4’ glucose chain with Alpha-1,6’ glucose branching
Cellulose (2)
Dietary fiber, Beta-1,4’ glucan
Ribonucleoside
Base + D-ribose
Ribonucleotide
Base + D-ribose + Phosphate
3 DNA Components
- 2’-deoxy-D-ribose-phosphate backbone
- 3’-5’ phosphodiester linkage
- 1’-Beta-glycolidic linkage to bases
Chargaff’s Rule
Amount of A equals amount of T and amount of G equals amount of C in DNA samples
5 Structural Properties of DNA
- Antiparallel double strands
- Right-handed helical twist
- Phosphate sugar backbone outside w/ (anti)-bases inside, resulting in major and minor grooves
- Complementary H-bonded AT and CG base pair planes perpindicular to helical axis
- Sequential base pairs stack along helical axis, 10bp per helical turn
Topoisomers
DNA molecules w/ same number of base pairs that differ in coiling amount
Prokaryotic vs. Eukaryotic DNA
Proks have circular plasmids whereas euks have linear chromatin
DNA Central Dogma
DNA transcribes RNA translates protein
3 Differences bw Prok and Euk mRNA
- Proks have polycistronic, euks have monocistronic
- Euks have 5’ 7-methylguanosine triphosphate cap
- Euks have 3’ poly-A tail
2d and 3d Representations of tRNA
2d - cloverleaf
3d - L shape
Prok Ribosome Sizes (3.3)
70S total
50S w/ 23S and 5S
30S w/ 16S
Euk Ribosome Sizes (3.4)
80S total
60S w/ 28S, 5.8S, and 5S
40S w/ 18S
2 Kinds of Polypeptide Rotation (+ point of each)
Phi: HN-Calpha rotation - heavily limited
Psi: Calpha-CO rotation - for alpha helices and beta sheets
2 Stabilizing Factors of Alpha Helix
- Main chain H-bonding bw C=O and HN
2. Side chains projecting out
3 Destabilizing Factors of Alpha Helix
- Branching Side Chains from CBeta (V,I,T)
- H-bonding side chains compete w/ main chain (S,D,N)
- Proline ring has no main chain NH so produces kink of not last in helix
Alpha Helix Structure
60 deg Psi angle gives “coiled” main chain
Beta Sheet Structure
150 deg Psi angle gives “extended” main chain
Parallel vs. Antiparallel Beta Sheets
Parallel: Each AA H-bonds w/ 2 different AAs of adjacent strand
Antiparallel: Each AA H-bonds (twice) w/ 1 other AA of adjacent strand
Loops (2)
Connect repetitive secondary structure elements, often on protein surface to mediate interactions w/ other molecules
4 Alpha Domain Tertiary Structures
Helix bundles
Globin fold
Homeodomain
Alpha solenoid
3 Beta Domain Tertiary Structures
Beta Barrels
Beta Propellers
Immunoglobin fold
Helix Bundles
3-4 alpha helices tightly packed in coiled coil fashion
Homeodomain
C-terminal helix roughly perpendicular to N-terminal helix-turn-helix pair
Globin Fold
Alpha helices (8) tightly packed
Alpha Solenoid
Alpha helices arranged in curved pattern that resembles jelly roll
Beta barrel
Large antiparallel beta sheet that twists to a closed structure
Beta propellers
Blade shaped beta sheets (4 antiparallel strands) arranged toroidally around a central axis
Immunoglobin Fold
Two layer sandwich of antiparallel Beta strands in two sheets w/ Greek key topology
2 Components of Salt Bridges
H-bonding and electrostatic attraction
Alpha/Beta Barrels (3)
Closed parallel 8 Beta sheet structure with interconnecting alpha helices packed on outside of the barrel
One of the most common protein folds
Active site residues always located w/in C-terminal loops
Alpha/Beta Twists
Open parallel 4-10 Beta sheet structure w/ interconnecting alpha helices packed on both sides of sheet
Rossman Fold
Six parallel Beta strands linked to four alpha helices