Nonenzymatic Protein Function and Protein Analysis Flashcards
What is collagen?
contains a trihelical fiber and makes up most of the extracellular matrix of connective tissue and is important for providing strength and flexibility
What is elastin?
important component of extracellular matrix of connective tissue; acts like a spring
What is keratins?
intermediate filament proteins found in epithelial cells; contribute to the mechanical integrity of the cell and function as regulatory proteins
What is actin?
makes up microfilaments and thin filaments in myofibrils
What is tubulin?
protein that makes up microtubules
What are motor proteins?
display enzymatic activity, acting as ATPases that power the conformational change necessary for motor function
What is myosin?
primary motor protein that interacts with actin; acts as thick filament in myofibril, also involved in cellular transport
What are kinesins?
play a role in aligning chromosomes during metaphase and depolymerizing microtubules during anaphase of mitosis, important for vesicle transport in the cell - move neurotransmitters toward the synaptic gap
What are dyneins?
involved in the sliding movement of cilia and flagella, important for vesicle transport in the cell - reuptake neurotransmitters towards the soma
What are binding proteins?
these are proteins that stabilize functions in individual cells and the body and transport or sequester molecules by binding to them
What are examples of binding proteins?
hemoglobin, calcium-binding proteins, DNA-binding proteins
What are cell adhesion molecules (CAMs)?
proteins found on the surface of most cells and aid in binding the cell to the extracellular matrix or other cells
What are cadherins?
a group of glycoproteins that mediate calcium-dependent cell adhesion; hold similar cell types together
What are integrins?
a group of proteins that all have two membrane-spanning chains called alpha and beta that help with binding and communicated with the extracellular matrix; also play role in cellular signaling and can greatly impact cellular function by promoting cell division, apoptosis, or other processes
What is selectins?
bind to carbohydrate molecules that project from other cell surfaces; expressed on white blood cells and endothelial cells that line blood vessels; host defense
What are antibodies?
proteins produced by B-cells that function to neutralize targets in the body, such as toxins and bacteria, and then recruit other cells to help eliminate the threat
What keeps the heavy and light chains of antibodies together?
disulfide linkages and noncovalent interactions
What is biosignaling?
a process in which cells receive and act on signals; act as extracellular ligands, transporters for facilitated diffusion, receptor proteins and second messengers
What is an ion channel?
proteins that create specific pathways for charged molecules
What is facilitated diffusion?
the diffusion of molecules down a concentration gradient through a pore in the membrane created by this transmembrane protein (ie ion channel); used for molecules that are impermeable
What is an example of an ungated ion channel?
potassium channels which exist in every cells
What are voltage-gated ion channels?
gate is regulated by the membrane potential change near the channel
What are ligand-gated channels?
the binding of a specific substance or ligand to the channel causes it to open or close
What is an example of a ligand-gated channel?
chloride channel that needs GABA to bind to it
What is a membrane-spanning domain?
anchors the receptors in the cell membrnae
What is the ligand-binding domain?
stimulated by the appropriate ligand and induces a conformational change that activated the catalytic domain which initiates a second messenger cascade
What are G protein-coupled receptors?
are a large family of integral membrane proteins involved in signal transduction; characterized by seven membrane spanning alpha helices
What is the formula for migration velocity of electrophoresis?
V = E*z/f E = electric field strength z = net charge on the molecule f = frictional coefficient
What is polyacrylamide gel electrophoresis (PAGE)?
method for analyzing proteins in their native states; most useful to compare the molecular size or the charge of proteins
What is sodium dodecyl sulfate - polyacrylamide gel electrophoresis (SDS-PAGE)?
separates proteins on the basis of size alone. Adds detergent that denatures the protein and neutralizes its charge so only the size affects its movement
What is the isoelectric point?
the pI is the pH at which the protein or amino acid is electrically neutral, with an equal number of positive and negative charges
What is isoelectric focusing?
proteins that are positively charged migrate to the cathode and proteins that are negatively charged move to the anode; they stop when they reach the portion of the gel where the pH is equal to the pI
