Ch 3: Nonenzymatic Protein Functioning & Protein Analysis (4%)

structural proteins

Name the Nonenzymatic-Molecule

compose the cytoskeleton, anchoring proteins, and much of the extracellular matrix; generally fibrous in nature: include collagen, elastin, keratin, actin, and tubulin

motor proteins

Name the Nonenzymatic-Molecule

have one or more heads capable of force generation through a conformational change; have catalytic activity; include myosin, kinesin, and dynein

binding proteins

Name the Nonenzymatic-Molecule

bind a specific substrate, either to sequester it in the body or hold its concentration at steady state

antibodies (aka immunoglobulins, Ig)

Name the Nonenzymatic-Molecule

used by the immune system to target a specific toxin or protein on the surface of a pathogen

cell adhesion molecules (CAM)

Name the Nonenzymatic-Molecule

allow cells to bind to other cells or surfaces; always integral membrane proteins

Cadherins

cell adhesion molecules (CAM) that hold similar types of cells together

Integrins

cell adhesion molecules (CAM) that help cells adhere to proteins in the extracellular matrix; some also have signaling capabilities; involved in white blood cell migration

Selectins

cell adhesion molecules (CAM) that help cells adhere to carbohydrates on the surfaces of other cells; most commonly used in the immune system; involved in white blood cell migration

Electrophoresis

Protein Isolation

uses a gel matrix to observe the migration of proteins in response to an electric field

electric field, charge, size, anode, cathode, small, large, faster, slower

Protein Isolation

Electrophoresis works to separate proteins by subjecting compounds to an _________ _______, which moves them according to their _________ and _______. Negatively-charged compounds will migrate toward the positively-charged _________ and positively-charged compounds will migrate towards the negatively-charged _________. The gel acts like a sieve, allowing ________ particles to pass through easily while retaining ________ particles. Therefore, a molecule will move __________ through the medium if it is small, highly charged, or placed in a large electric field. Conversely, molecules will migrate __________ through the medium when they are bigger and more convoluted, electrically neutral, or placed in a small electric field.

Native PAGE

Protein Isolation

the type of electrophoresis that maintains the protein’s shape, but results are difficult to compare because the mass-to-charge ratio differs for each proteins

SDS-PAGE

Protein Isolation

the type of electrophoresis that denatures the proteins and masks the native charge so that comparison of size is more accurate, but the functional protein cannot be recaptured from the gel

Isoelectric-Focusing

Protein Isolation

the type of electrophoresis that separates proteins by their isoelectric point (pI); the protein migrates toward an electrode until it reaches a region of the gel where pH = pI of the protein

X-Ray Crystallography

Protein Analysis

Which method of protein analysis is the one that has been used to identify 75% of today’s known protein structures and is the most reliable?

NMR

Protein Analysis

Which method of protein analysis is the one that has been used to identify 25% of today’s known protein structures and is less reliable?

Edman Degradation

Protein Analysis

a method of identifying the primary structure of a protein; selectively and sequentially removes the N-terminal amino acid of the protein, which can then be analyzed by mass spectroscopy; best for smaller proteins

Bradford Protein Assay

Protein Analysis

a method of determining the concentration of a protein in solution; mixes a protein in solution with Coomassie Brilliant Blue dye, where increased protein concentrations correspond to a larger concentration of blue dye in solution; very accurate when only one type of protein is present in solution, but is less accurate when multiple proteins are present Bradford