Conformational Change

Documents about Conformational Change

	Lec 8 - Eye-Photoreception-Early Visual Pathway... USC, BISC 421 Excerpt: ... Lecture8:Eye/Photoreception/EarlyVisualPathway:15Oct08 FinishingupVisceromotorCtrl: AfferentstotheVisceralMotorSystem AutonomicControlofCardiovascularFunction AnatomyoftheHumanEye RefractiveErrors Accommodation SurfaceoftheRetina Structureofth ...
	Hexokinase Purdue, CHM 333 Excerpt: ... Conformational change s in yeast hexokinase on binding glucose. ...
	09_ATPRecovered San Diego State, BIOL 100 Excerpt: ... s a change in the shape of the protein. The protein undergoes a conformational change meaning that it no longer has the same shape. As a consequence of the conformational change , the thermodynamics have changed allowing a reaction to occur. The bottom line is that ATP causes a conformational change in a molecule that then allows chemical reactions to occur. Below is an example of how ATP works in making a protein change its thermodynamic property. In succeeding lectures, you will be exposed to the various kinds of structures that proteins have in biological solutions. Presently, appreciate the fact that ATP will alter the biological shape of the protein allowing reactions to occur. In brief, ATP can work to change the shape of the protein to allow a reaction to occur. Usually, the terminal phosphate is used to modify the structure of the reactants, but in some cases, it is adenosine products that can also do the trick. Figure 3: ATP hydrolysis causes protein structure change. Figure 2: Energy Reaction in a ...
	studyguide-hsqc Washington University in St. Louis, BIO 5325 Excerpt: ... mpression of the state of the protein sample. A well structured protein yields a nicely resolved 2D HSQC spectrum like the one shown on p. 13 of the NMR III lecture handout. The peaks are spread out over a wide chemical shift range (good chemical shift dispersion). Typically, the amide proton chemical shifts cover most of their full range of approximately 6.5 10 ppm. Conversely, a protein that is unfolded or disordered may show amide proton peaks that overlap and cluster in the 8 8.5 ppm range. If you have engineered a protein domain from a larger protein, HSQC can be used to assess whether the isolated domain is folded and well structured. 2. To monitor how the protein conformation changes with sample conditions: HSQC spectra can be collected at different pH, temperature, salt and denaturant concentrations to monitor backbone conformation. If the resonances are assigned, specific conformational change s can be mapped and characterized in a residue- and site-specific manner. 3. To follow equili ...
	Lecture 7 Notes Stony Brook University, BIO 202 Excerpt: ... BIO 202 Notes Lecture 7: Enzymes and regulation of enzymes Chapter 8: An Introduction to Metabolism 8.5 Regulation of enzyme activity helps control metabolism All of a cells metabolic pathways cannot operate simultaneously: chaos if they did Metabolic pathways are regulated by when are where its enzymes are active Genes that encode specific enzymes can be switched on and off The activity of enzymes can be regulated once theyre made Allosteric Regulation of Enzymes A proteins function at one site is affected by the binding of a regulatory molecule to a separate site (like a reversible noncompetitive inhibitor) Inhibition or stimulation of an enzymes activity Allosteric Activation and Inhibition Most allosterically regulated enzymes are constructed from subunits (two or more polypeptide chains) Each subunit has its own active site Subunits are fit together so that a conformational change in one is transmitted to all Whole enzyme oscillates between ...
	BIOS41_Lecture6_01252008 Lehigh, BIOS 41 Excerpt: ... BIOS 41 Biology Core I Cellular and Molecular Spring 2008 Professor J. A. Sands Lecture 6, January 25 Proteins, continued (Chapter 4, pages 143-159) The binding of a protein to another molecule is highly selective. 04_30_selective binding.jpg 04_31_specific ligands.jpg Binding sites allow a protein to interact with specific ligands. An antibody has two identical binding sites for its antigen. 04_32_antibody.jpg Lysozyme illustrates how an enzyme works. Lysozyme cleaves a polysaccharide chain. 04_33_Lysozyme.jpg In the active site of lysozyme, bonds are bent and broken (details shown in Figure 4-34). Enzymes can encourage catalysis in several ways. 04_35_Enzymes.jpg Binding of a small regulatory molecule can cause a conformational change . 04_39_conform.change.jpg 04_41_phosphorylation.jpg Protein phosphorylation is a common means of regulating protein activity. 04_42_molec. switches.jpg GTP-binding proteins form molecular switches. Changes in confor ...
	Lecture10 UC Davis, BIS BIS102 Excerpt: ... Lecture 10 1/30/09 Background reading: Garrett and Grisham: Chapter 6: Pages 194-201 Chapter 15: Bottom of Page 491- 497 Outline: Quaternary structure (IVo structure) Hemoglobin Comparison of hemoglobin with myoglobin Conformational change s occur when hemoglobin binds to oxygen. Quaternary structure (IVo structure) Many of the larger globular proteins are oligomeric complexes formed by the association of separate folded polypeptide monomers. These monomers are called subunits. Quaternary structure is a level of protein structure that refers to the manner in which these subunits specifically associate with one another to form the native protein. Depending upon the protein, these structures can be composed of identical or nonidentical protein subunits and can vary in the number of subunits they contain. Examples: Proteins that consist of identical subunits: Homodimers Homotetramers Examples (continued): Proteins that consist of different subunits: Heterodimers Heterotetramers Heter ...
	MCB Chapter 12 notes BC, BI 304 Excerpt: ... a cell, since ions cannot diffuse readily across the lipid bilayer of a membrane cells must maintain osmotic balance and electrical neutrality despite large differences in solute concentrations across cell membranes ions and hydrophobic molecules have low permeabilities.need to be transported across somehow o Membrane transport proteins fall into two classes: carriers and channels very large and diverse protein family.large number of transporters lots of molecules need to be transported (sugars, amino acids, nucleotides, ions, atp, protons) differ from membrane to membrane according to membrane function universal features: alpha-helical, multispan proteins that have a hydrophobic interior and a hydrophilic exterior carrier proteins bind their solute with great specificity, facilitates transport only for those solutes that fit specifically to their binding site, conformational change s occur that allow the release and uptake of solute into/out of the cell channel proteins are far less specific and discr ...
	Lec 9 - Photoreception-Early Visual Pathway Pt ... USC, BISC 421 Excerpt: ... Lecture9:Photoreception/EarlyVisualPathwayContinued A.Khan,17Oct08 StructureoftheRetina StructureoftheRetina FunctionofthePigmentEpithelium LightHyperpolarizesPhotoreceptors CyclicGMPGatingofChannelsinRodOuterSegment CyclicGMPGatingofChannelsin ...
	080818.PMCB.lecture.3 UF, PCB 5530 Excerpt: ... lymerase III is the major enzyme involved in DNA replication Kornberg, DNA Replication, 1980 E. Coli DNA Polymerase Activities and Features DNA Polyermase I Kornberg, DNA Replication, 1980 Structure of DNA Polymerases Reverse Transcriptase: Domain Structure 8/18/2008 PMCB Lecture 5: G. Peter 8 Conserved Structure of DNA Polymerases Molecular Cell, Vol 8, 417-426, August 2001 DNA Polymerase Mechanisms are Conserved Sequence of Steps During Polymerization Binding DNA template-primer Binding of incoming dNTP Formation of phosphodiester bond Release of pyrophosphate Translocation of complex to the next 3 OH terminus Nucleotide selection by base pairing and conformation changes in the polymerase account for ~100,000 fold of the fidelity of replication Four Mechanisms that Control the Fidelity of DNA Replication in DNA Polymerases Complementary base pairing H-bonding Base pair geometry Conformational change s induced by DNA and dNTP binding Removal of incorrect nucleotides a ...
	Lec15B.Transport1.08 Rochester, B 110 Excerpt: ... 1 Transporters provide selective advantage The growth rate is limited by the rate of uptake of needed precursors from the organic soup New population of cells -B E.g., A new membrane protein that acts as a nucleotide transporter # cells or cell ma ...
	Lecture9 East Los Angeles College, C 7004 Excerpt: ... activity is often regulated by both allosteric inhibitors (feedback) and also covalent modification. Allosteric enzymes (compare also haemoglobin) These often show sigmoid kinetics (i.e. non-Michaelis-Menten): A consequence of this sigmoid kinetics is that such enzymes are very sensitive to small changes in substrate concentration. Sigmoid kinetics is a consequence of interaction between sites. Once one active site has bound substrate, others are more likely to do so (i.e. they have more than one active site). It may also be due to the presence of sites that bind substrate other than the active site. If there is more than one active site these are normally some distance away from each other (often on different subunits). If what happens at one site is going to influence what happens at another site the only way that this can happen is by a conformational change in the protein. The protein switches between two alternate conformations, one active and the other inactive (or less active). The switching can also ...
	celllecture3 N. Arizona, ES 64 Excerpt: ... Lecture 3 BIO 344 Hydrophobic amino acids in green and yellow Predicting transmembrane helices from the amino acid sequence Secondary structure of protein Examples of -barrels Detergent Micelle in Water DVD clip 38 Structures of Two Commonly Used Detergents Liposome for studying membrane properties Membrane Proteins in Human Red Blood Cells Most Membrane Proteins have Structural Functions Freeze Fracture Electron Microscopy Band 3 can be seen as intramembrane particles, more on P face than E face DVD clip 41 Membrane Transport of Small Molecules and the Electrical Properties of Membranes Chapter 11 Molecule movement across lipid bilayer without proteins Permeability across lipid bilayer Carrier Proteins Channel Proteins Passive vs. Active Transport Three Ways of Driving Active Transport Electrochemical gradient vs. membrane potential Can work additively or against each other Three Ways of Driving Active Transport Conformational Change in Carrier Protein ...
	Bchm4850_L5 Laurentian, BCHM 200803 Excerpt: ... Calorimetry Principles of Physical Biochemistry Van Holde, Johnson & Ho Pages 93-103 Lecture 5 Biochemistry 4850 Slide 1 Calorimetry Two common calorimetric methods in Biochemistry: 1) Differential Scanning Calorimetry (DSC) Measure changes in heat capacity as a function of temperature Useful for identifying phase transitions (ie. conformational change s) 2) Isothermal Titration Calorimetry (ITC) Measure changes in enthalpy as a function of protein or ligand concentration Preferred method for quantifying binding interactions Note: 'bomb' calorimetry is a constant volume measurement DSC and ITC are constant pressure measurements qv=E qp=H Lecture 5 Biochemistry 4850 Slide 2 Experimental Calorimetry The Keq of a conformational change or binding interactions can be measured by identifying the concentrations of all components at equilibrium From the Keq, it is straightforward to calculate G G = -RT ln Keq How do we measure the H and S components? van't Hoff Relationship G = - RT ln Keq = H ...
	766_single_mol.ppt National Taiwan University, BIOCHEM 766 Excerpt: ... Single Molecule Methods Microscopy, optical tweezers, FRET Getting away from the ensemble: -Heterogeneity - Rare events BCT 9:13, Bustamante et al. 2003 Nature Electron microscopy ds DNA ss DNA Lambda repressor-DNA complex Note persistence length difference But, EM (cryo-EM) involves study of "dead" molecules - can't see them "in action" Single molecule spectroscopy: FRET Ha et al. 1999 "Ligand-induced conformational change s observed in single RNA molecules" PNAS 96(16) 9077-9082 Single molecule sensitivity and resolution by combining FRET + near-field scanning optical microscopy (pseudo coloring: green, donor emission; red, acceptor emission) Protein-induced conformational change s by single molecule FRET (a) Proximity factor histograms after incubation with S15 protein (b) Proximity factor histograms for RNA preincubated w/ 3 nM S15; time-dependent decrease is due to dissociation In solution experiments, would not see the distribution, only the average Ha et al. 1999 Kinetics of arm movement Tim ...
	ligand_receptor_model Maryland Baltimore, PHAR 531 Excerpt: ... a drug associates and dissociates from the receptor: each encounter elicits a response. agonist: association is fast and dissociation is fast antagonist: association is fast, dissociation is slow (i.e. drug stays bound to the receptor) limitations: i) doesn't rationalize differences in biological activity between structurally similar compounds ii) relationship between binding strength and biological activity fails: based on the above definition an agonist will bind less tightly than an antagonist, however, this is often not accurate (Kassoc = kon/koff) 3) Induced-Fit Theory Approach of drug to receptor induces a conformational change of the active (binding) site of MacKerell, Ligand-Receptor Model of Drug Action the receptor. It is the conformational change that initiates the pharmacological response. Note that the drug itself can also change conformation (as with acetylcholine). agonist: binds and induces the correct conformational change antagonist: binds but doesn't induce the correct conformational cha ...
	L4_08 UCSC, BIO 110 Excerpt: ... nce (voltage gradient) across them with the inside usually negative with respect to the outside. The flow of ions through a membrane channel protein is driven by the electrochemical gradient for that ion (i.e. the voltage gradient and the concentration gradient). When these two influences balance each other, the electrochemical gradient is 0. NO NET FLOW. Called the equilibrium potential and it is calculated by the Nernst Equation. V=RT/zF ln [C]out/[C]in p634 4th ed p670 5th ed V= equil potential in volts C = concentration of ions R= gas constant T = temperature F = Faradays constant z= valence of ion A model of how conformational change s in a transporter can mediate passive movement of a solute Carrier proteins behave like enzymes, the process can be facilitated and it can be saturated. Vmax: saturated transporter at maximal velocity Km: affinity for solute. 1/2 Vmax approximates Km Only carrier proteins can mediate active transport. Here are 3 ways of driving active transport 3 types of transpo ...
	W6OutlineLec15 UC Irvine, BIOL D103 Excerpt: ... t in signaling, never found in alpha helical region Summation of amino acid interactions dictate overall protein interactions with other proteins -change one or two Amino acids CONFORMATIONAL CHANGE Calmodulin-binding of Ca2+ (ligands) interacts with acidic a.a. and completely changes the structure (to cause conformational change s) affinity-strength with which someone holds on specificity-selection of one ligand over another pointless to remember ALL subdomains Y(a.a.)# (location is peptide chain) gets phosphorylated p(hosphorylate hydroxyl group)A.A.# -cannot phosphorylate one at a time, both residues much be phosphorylated at once by special kinase (adds Phosphate) ...
	MCB 2007 September 21st Lecture Notes BC, BI 304 Excerpt: ... September 21st Lecture Notes: Membrane Proteins (Ch. 11 still): carry out most membrane function o transport ions and particular nutrients across the membrane (allow polar molecules to pass through the hydrophobic interior of the membrane) o anchor the membrane to macromolecules on either face (cytoskeleton, connect cells together in tissues) o act as receptors for chemical signals (extra-cellular domain binds with a ligand, triggers a conformational change in the cytosolic face, thus triggering a signaling pathway) o act as enzymes to catalyze certain reactions can associate with the lipid bilayer in various ways o transmembrane proteins (cross through the bilayer, have both hydrophilic and hydrophobic regions) o membrane-associated proteins (associate with the inner leaflet of the bilayer with an exposed amphipathic alpha-helix on the protein surface) o lipid-linked (attached covalently to lipid groups) o o roughly classified as INTEGRAL (can be removed only with detergents) or PERIPHERAL (can be separat ...
	Lecture5_08_Handouts Virginia Tech, BIOL 2104 Excerpt: ... ement by GTP is often stimulated by a signal received by the cell Conformational change s allow motor proteins to generate the forces responsible for muscle contraction and cell movement Binding sites of antibodies can be changed by mutation without altering the structure of the antibody itself 6 Antibodies How do we study proteins? Proteins can be separated by chromatography or by gel electrophoresis 7 Three different types of chromatography 8 Homework -Question 4-8 -Question 4-10 -Question 4 14 Question 4-14 -Question 4-17 -Question 4-19 9 ...
	Quiz7key N.E. Illinois, UX 3300 Excerpt: ... ic side phosphorylates Asp-369, inducing a conformational change that transports the 3 Na+ ions out of the cell. This conformational form of Na+,K+ATPase (E2) has a low affinity for Na+ ions. + 3) 2 K ions from the outside of the cell bind with high affinity to Na+,K+ATPase (E2 conformational form). 4) Dephosphorylation (hydrolysis of the phosphate from Asp-369 upon binding a new ATP molecule) induces a conformational change that transports 2 K+ ions into the cell. This conformational form of Na+,K+ATPase (E1) has a low affinity for K+ ions. 4. (7 Points) Nitrogenous Bases, Nucleotides and Nucleic Acids. a) Draw the five nitrogenous bases below. Label each one with its name and whether it is a pyrimidine or purine. pyrimidine pyrimidine pyrimidine purine purine b) On the structures above, CIRCLE all of the hydrogen bond donors and SQUARE all of the hydrogen bond acceptors. c) In the Watson-Crick base pair G:C, how many hydrogen bonds are formed? _three_ d) Indicate wi ...
	Lect_18cont_202 SUNY Stony Brook, BIO 202 Bio 202 Excerpt: ... Cell Communication: Cont. Lecture #18 Campbell: Chapter 11, pages 201-217. The Three Stages of Cell Signaling s 1. Reception s 2. Transduction s 3. Response Cell Communication s Part 3 - Response s Signal Transduction Pathways Signal Transduction Pathways s Signal Transduction Pathways are usually multi-step. A few molecules transmit a signal to multiple molecules resulting in an amplification of the signal. A very small number of signal molecules yields a major cellular response. Signal Transduction Pathways s Molecules that relay the signal from the receptor to the response are referred to as relay molecules. The signal is passed from one molecule to another and usually results in conformational change s in proteins along the pathway. Very often these conformational change s are induced by phosphorylation steps. s s Protein Phosphorylation s Phosphorylation of proteins is a major mechanism for regulating the activity of proteins, moving from an inactive to an activ ...
	LECTURE-10_Enzymes Stony Brook University, BIO 202 Excerpt: ... ty s A non-competitive inhibitor is structurally unrelated to the substrate. A non-competitive inhibitor does not bind to the active site of the enzyme. Usually a non-competitive inhibitor will bind to the enzyme irreversibly and cause a conformational change in the enzyme so the substrate can not effectively bind to the active site. Increasing the substrate concentration can not overcome the effect of a non-competitive inhibitor. s s s Inhibition of Enzyme Activity Regulation of Enzyme Activity s Once an enzyme is synthesized, its activity can be regulated or modulated. Metabolic pathways are often regulated by strategic enzymes at or very near the beginning of the pathway. Often, these enzymes are more complex and their activity can be regulated in the + or direction. Such regulatory molecules behave like reversible non-competitive inhibitors. s s s Allosteric Enzymes s Allosteric enzymes usually have a more complex quaternary structure. Allosteric enzymes often exist in two forms, an act ...
	3690 in-class test description Maple Springs, SOCI 3690 Excerpt: ... In-class Test (worth 20%) The test will take place on March 10 and will involve answering 2 short questions (worth 5% each), and one longer essay question (worth 10%). Questions will cover the readings, lectures and visual contents of the entire cour ...
	Homework_set2 Drexel, PHYS 750 Excerpt: ... Homework set #2 2. It was shown in the lecture that the finite size of the AFM tip would broaden the lateral dimensions of an object in the AFM images. For example, a rectangular object of length L and height h, the apparent length in the image will be W = L + 2 h(2 R - h ) , when scanned with a spherical tip of radius R. Derive an expression for the apparent length of the rectangular object if it is scanned with a parabolic tip with a radius of curvature R at the end. w L h x y 2. Two identical spherical molecules of radius r = 5 nm are scanned with spherical tip of radius R=20 nm. In order to resolve the two molecules in the AFM image when they are place side by side, what must be the vertical detection limit (i.e., the smallest detectable vertical movement of the tip) the of the AFM? All the objects and the substrate surface can be assumed to be rigid. tip 3. If you wish to study the protein-induced conformational change of DNA, such as bending, with the AFM, how long a fragment of DNA do you have to u ...