Documents about Amino Acid Residues
08 PS 2
Laurentian, ENZYME 420
Excerpt: ... 2008 BIOC 420 Problem Set (2) (due date: Sep 23) Find, through literature search, an example of perturbed pKa of amino acid residue in an enzyme. Provide brief descriptions on the enzyme, the reaction catalyzed by the enzyme, the role of the residue ...
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CHAPTER 4 (Figures)
Rutgers, BIOCHEM 301
Excerpt: ... David L. Nelson and Michael M. Cox Lehninger Principles of Biochemistry Fourth Edition Chapter 4: The Three-Dimensional Structure of Proteins Copyright 2004 by W. H. Freeman & Company Protein Secondary Structure Secondary structure refers to local conformation of some part of the peptide. These structures include 1. a-helix 2. b-sheets and 3. b-turns 2 Protein Secondary Structure i. The a-helix This is the most common protein secondary structure. The simplest arrangement the polypeptide chain assumes with its rigid bonds a helical structure, which Pauling and Corey called the a-helix (Fig. 4-4). In this structure, the polypeptide backbone is tightly would around an imaginary axis drawn longitudinally through the middle of the helix, and the R groups of amino acid residues protrude outward from the helical backbone. Repeating unit is a single turn of the helix, which extend about 5.4 along the axis. The amino acid residues in an a-helix have conformation with = -45 ...
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Peptides_09
Arizona, BIOC 460
Excerpt: ... BIOC 460 Summer 2009 Peptides and Protein Primary Structure Reading: Berg, Tymoczko & Stryer, 6th ed., Chapter 2, pp. 34-37 Work on Peptide Ionization Practice Problems on Lecture Notes page. Problems in textbook: chapter 2, pp. 63-64, #6,7,8,13,14 Molecular Graphics Routines: Jmol structure showing planarity of peptide bond: http:/www.biochem.arizona.edu/classes/bioc462/462a/jmol/peptide/peptide.html Animation of phi () and psi () angles (dihedral angles for an amino acid residue): http:/www.biochem.arizona.edu/classes/bioc462/462a/NOTES/Protein_Structure/Rama_animationhtm.htm 1 Peptides/Primary Structure 1 BIOC 460 Summer 2009 Key Concepts Proteins: primary structure Peptide bond amide linkage holding amino acid residues in peptide and protein polymers (primary structure of proteins). Product of condensation of 2 amino acids Posttranslational modifications of amino acids/proteins Examples: hydroxylation of some Pro and Lys residues in collagen (vital for collagen struct ...
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PS2key
N.E. Illinois, UX 3450
Excerpt: ... A chain and the B chain, resulting in PTH-derivatives of glycine and phenylalanine and polypeptides of the A chain and B chain with one less amino acid residue at the N-terminus. This process could be repeated to sequence the entire A chain and the B chain of insulin. Although without separating these two polypeptides prior to Edman degradation, it would be difficult to determine which Nterminal amino acid is cleaved from which polypeptide. (d) Reaction of the product(s) of (b) with carboxypeptidase A Carboxypeptidase A cleaves (hydrolyzes) the C-terminal peptide bond of all amino acid residues except proline, arginine, and lysine. The C-terminal amino acid is asparagine in the A chain and alanine in the B chain, so both amino acid residues will be cleaved, resulting in polypeptides of the A chain and B chain with one less amino acid residue at the C-terminus. (e) Reaction of the product(s) of (b) with chymotrypsin Chymotrypsin cleaves the peptide bond on the C-terminal side of phenylalanine, tyrosin ...
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lecture2_qualquestion_answer
Berkeley, MCB 200
Excerpt: ... Answer Key - Quantitative Question from Lecture #2 The high [Mg2+] concentration in the in vitro translation reaction allows for AUGindependent initiation. A codon is a three-nucleotide sequence. You are given that the synthetic mRNA is composed of equal amounts of A and U. Thus, the total number of possible codons in the artificial transcript is 23 (i.e. 2 x 2 x 2) = 8 codons. In a totally random hetero-copolymer of A and U, these codons would be: AAA = Lys UAA = Stop AUA = Ile AAU = Asn UUA = Leu UAU = Tyr AUU = Ile UUU = Phe Because the probability of finding each of these codons in the RNA is equal (because the probabilities of finding A or U at any given position in the RNA are equal), you should get, as the product of in vitro translation, a mixture of peptides (because the Stop codon will occur with a frequency as great as that for any of the individual amino acid residues , except Ile) that are composed of the following amino acid residues in the indicated molar ratios: Asn:Ile:Leu:Lys:Phe:Tyr:1:2:1: ...
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S06.Polypep
Rochester, B 110
Excerpt: ... 1 Polypeptides ( Proteins ) Facts I. Polypeptides are polymers of subunits ( amino acid residues ) A. There are 20 common "free" amino acids 1. All amino acids have a general structure and a unique variable group ( R-group, Side Chain ) a. R groups differ in charge/polarity & size ) B. Peptide ( -C-N-) bonds l ink amino acids in a polypeptide 1. Polypeptides have amino ("N") & carboxyl ("C") ends/terminals I. The term protein usually refers to the functional structure a polypeptide adopts in a cell 1. A functional complex including 2 or more polypeptide is often called a protein 2 A closer look at Polypeptides ( Proteins ) ~ 29% mass = Biomolecules ~ 19 % polypeptides ~ 6 % polynucleotides ~ 2 % polysaccharides ~ 2 % lipids ~ bacteria Polypeptides are polymers of subunits ( amino acid residues ) 3 E.g., Lysozyme contains 129 amino acid "residues" lysozyme #1 Amino acid residues "Unravel" #20 #129 #80 #100 #40 4 The sequence of amino acid residues in lysozyme Pro Ile Gln Thr Phe Lys Cys Trp Asn Ser ...
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MidtermS09Grp
Delaware, C 342
Excerpt: ... ide chain of 153 amino acid residues of known sequence and a single iron protoporphyrin, or heme, group. The same heme group is found in hemoglobin, the oxygenbinding protein of erythrocytes, and is responsible for the deep red-brown color of both myoglobin and hemoglobin. Myoglobin is particularly abundant in the muscles of diving animals such as the whale, seal, and porpoise. Storage and distribution of oxygen by muscle myoglobin permit these animals to remain submerged for long periods of time. Hemoglobin (Mr 64,500) is a tetrameric protein containing four heme prosthetic groups, one associated with each polypeptide chain. Adult hemoglobin contains two types of globin, two chains (141 residues each) and two chains (146 residues each) Although fewer than half of the amino acid residues in the polypeptide sequences of the and subunits are identical, the three-dimensional structures of the two types of subunits are very similar. Furthermore, their structures are very similar to that of myogl ...
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Quiz6
N.E. Illinois, UX 4860
Excerpt: ... CHM 4860 (Dr. Tremain) QUIZ #6 (Take-Home) Due 3 pm Nov. 12th, 2008 NAME_ 1. (4 Points) The Genetic Code. a) How many codons (list them) can mutate to become nonsense codons (termination or stop codons) through a single base change? List the amino acid that that each of these codons encoded before the single base change. b) Explain nonsense suppression. c) Which of the amino acids above in your answer to a) are MOST likely to be incorporated by a nonsense suppressor tRNA? Which of the amino acids above in your answer to a) are LEAST likely to be incorporated by a nonsense suppressor tRNA? Briefly explain. d) Explain the wobble hypothesis. Explain why this would be an advantage in terms of accelerating protein synthesis. Continued On Back! 2. (3 Points) Determine the minimum energy cost (in terms of ATP equivalent phosphoanhydride bonds expended) required for the biosynthesis of the -chain of hemoglobin (146 amino acid residues ) starting from a pool inc ...
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study questions 1
UC Davis, BIS bis2a
Excerpt: ... stick together through an hydrophobic interaction. Are the two proteins more likely to fall apart in pure water, salty water, or oil? 7. Two proteins stick together through numerous H-bonds. Are the two proteins more likely to fall apart in pure water, salty water, or oil? 8. Can a covalent bond be formed by sharing protons? 9. Explain the relationship between amino acids, peptides, polypeptides, proteins. 10. Consider a polypeptides that is made of 20 amino acid residues . The first and last five amino acids in the chain have highly hydrophobic side chains. What structure could this polypeptide form when it is dropped in water? 11. You and your pal just got shot up into space riding on top of the space shuttle with your own little rocket. The shuttle drops you off in deep space (no atmosphere). Your rocket has its own fuel tank, full of gasoline. You try to move by squirting your gasoline into the rocket tube and igniting it with a spark. Nothing happens. You have the nagging feeling that something is missing ...
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lecture_2
Ill. Chicago, CHEM 554
Excerpt: ... th each peptide bond are coplanar, as indicated by the rectangle Reference angles for (phi) and (psi) are defined as follows = 1800 when adjacent peptide N atoms are trans to the C-C bond. = 1800 when adjacent carbonyl C atoms are trans to the C-N bond. When = 00 and = 1800, there is a large steric interaction between adjacent peptide N-H groups. When = 1800 and = 00, there is a large steric interaction between adjacent peptide C=O groups. Therefore, not all sets of angles lead to stable structures. Secondary structure corresponds to conformations of segments of the polypeptide chain that are stabilized by H-bonding between the peptide C=O group of one residue and the peptide N-H group of another residue. Two types of secondary structure are most frequently observed. 1. Helical segments formed by a repeating set of angles of and for amino acid residues along the polypeptide chain with H-bonds approximately parallel to the long axis of the helix. The particular kind of heli ...
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AttendanceQuiz3key
N.E. Illinois, UX 3450
Excerpt: ... s heptapeptide at pH 14? g) Calculate the isoelectric point (pI) for this heptapeptide. NH3+ Glu pKa = 8 pKa = 4.3 Lys pKa = 10.5 Tyr pKa = 10.1 His pKa = 6.0 Arg pKa = 12.5 Met Ser COOH pKa = 13 pKa = 3.5 pH 1: NH3+Glu0Lys+Tyr0His+Arg+MetSer0COOH0 pH 5: NH3+GluLys+Tyr0His+Arg+MetSer0COO pH 7: NH3+GluLys+Tyr0His0Arg+MetSer0COO pH 9: NH20GluLys+Tyr0His0Arg+MetSer0COO pH 11: NH20GluLys0TyrHis0Arg+MetSer0COO pH 14: NH20GluLys0TyrHis0Arg0MetSerCOO pI = (8 + 10.1) = 9.05 Net Charge = +4 Net Charge = +2 Net Charge = +1 Net Charge = +0 (zwitterion) Net Charge = 2 Net Charge = 4 OVER 2. (4 Points) Use the following information to determine the amino acid sequence of -endorphin (a peptide containing 31 amino acid residues ): a) Hydrolysis of -endorphin produces the following amino acids: Tyr (1), Gly (3), Phe (2), Met (1), Thr (3), Ser (2), Lys (5), Gln (2), Pro (1), Leu (2), Val (2), Asn (2), Ala (2), Ile (1), His (1), Glu (1) b) Treatment wi ...
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Exam 1 Study Guide
University of Texas, BIO 311C
Excerpt: ... shes the different classes of amino acids? Can you describe the structure of a protein at different levels to the extent we covered in class (primary, secondary, tertiary, and quaternary)? Can you draw the basic structure of an amino acid and two amino acid residues joined by a peptide bond, identifying the bond? 5. What is the structure of a nucleic acid polymer and the monomer used to make the polymer? (Be able to draw as covered in class). What is a phosphodiester linkage? 5' and 3' ends? What is the difference between RNA and DNA? What are the names of the nitrogenous bases, their single letter abbreviations? Structure of double-stranded nucleic acids as antiparallel double helix What is meant by base pairing of nucleotides in a double stranded nucleic acid? Important points to learn about cellular structures and functions 1. Structure and functions of cellular structures What are the different types of microscopy we discussed, what types of light or electromagnetic beam is used for each and how does ...
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MCB 2007 September 21st Lecture Notes
BC, BI 304
Excerpt: ... and associate indirectly with the bilayer through usually covalent interactions o a polypeptide chain usually crosses the bilayer as an alpha helix the hydrophobic effect underlies integral membrane protein character in the bilayer made up of hydrophobic side chains that allow it to interact with the hydrocarbon interior of the membrane (van der waals interactions) (simplest, "most direct" solution, only requires 20 amino acid residues max at 1.5 angstroms per residue to cross the bilayer) multiple alpha-helices can form a transmembrane pore with a hydrophilic interior (transport proteins!) lined with hydrophilic resides, hydrophobic faces link the helices to each other and to the membrane, creates an aqueous pore o Beta-sheets can sometimes be found (Beta-barrels) exterior/membrane face will be hydrophobic, hydrophilic face makes the pore very large, low selectivity so not as common usually found in the outer membranes of bacteria and mitochondria antiparallel beta-sheets with a ...
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TOPIC 5
University of Ottawa, BIO 1140
Excerpt: ... ot carbon, not chiral carbon and not central carbon - label it alpha carbon or carbon) You may try these after you study this section. Describe briefly the basic nature of: (I have done so for some of the questions as an example of what I mean by brief and basic.) 1. alpha-helix: (= -helix) A particular helical folding of the polypeptide backbone in protein molecules (both fibrous and globular), in which the carbonyl oxygens are all hydrogen-bonded to amide nitrogen atoms three residues further along the chain. The translation of amino acid residues along the long axis is 0.15nm, and the rotation per residue, 100, so that there are 3.6 residues per turn. 2. conjugated proteins: 3. polymer: 4. heterotetramer: 5. homodimer: 6. monomer: 7. motif: - A small structural element that is recognizable in several proteins such as a coiled-coil alpha-helix or the -barrel 9. domain: -a term used to describe a part of a protein that has particular function, e.g. DNA-binding domain, ATP-binding domain. In proteins a do ...
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Beng 130 Lecture 5
UCSD, BENG 130, 103B,
Excerpt: ... and thus are fully allowed; medium blue indicates conformations allowed at the extreme limits for unfavorable atomic contacts; the lightest blue area reflects conformations that are permissible if a little flexibility is allowed in the bond angles. The asymmetry of the plot results from the L stereochemistry of the amino acid residues . The plots for other L- amino acid residues with unbranched side chains are nearly identical. The allowed ranges for branched amino acid residues such as Val, Ile, and Thr are somewhat smaller than for Ala. The Gly residue, which is less sterically hindered, exhibits a much broader range of allowed conformations. The range for Pro residues is greatly restricted because is limited by the cyclic side chain to the range of 35 to 85. Amino Acid Sequence Determines Tertiary Structure Dielectric Constants of Some Common Materials/Molecules FIGURE 427 Renaturation of unfolded, denatured ribonuclease. Urea is used to denature ribonuclease, and mercaptoethanol (HOCH2CH2SH) to ...
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worksheet
Binghamton, CHEM 332
Excerpt: ... id residue, look for the side chain of that residue. It will be connected to the alpha carbon, which will be connected to a nitrogen. Break the bond between the N and the carbonyl carbon of the adjacent residue. In your product, the nitrogen should become an NH2, and the carbonyl C should be a carboxylic acid. To cleave on the C-terminal side of some amino acid residue, look for the side chain of that residue. It will be connected to the alpha carbon, which will be connected to a carbonyl carbon. Break the bond between that carbon and nitrogen of the adjacent residue. In your product, the carbonyl C should be a carboxylic acid, and the nitrogen should become an NH2. Example: Thermolysin is a protease that hydrolyzes peptide bonds on the N-terminal side of Ile and Val, among other hydrophobic amino acid residues . Show the product of the reaction below. ...
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W2OutlineLec4
UC Irvine, BIOL D103
Excerpt: ... Luis David Gomez 59866865 Bio 192 D103 Cell Biology Week 2 Lecture 4 Outline 1/ 14/08 Ion Channels 10^7 to 10^8 ions/sec Two conformation: Closed/Open Selectivity Filter Specific A.A. guide ion through the channel K+ channel: selectivity based on siz ...
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AttendanceQuiz3
N.E. Illinois, UX 3450
Excerpt: ... s heptapeptide at pH 14? g) Calculate the isoelectric point (pI) for this heptapeptide. OVER 2. (4 Points) Use the following information to determine the amino acid sequence of -endorphin (a peptide containing 31 amino acid residues ): a) Hydrolysis of -endorphin produces the following amino acids: Tyr (1), Gly (3), Phe (2), Met (1), Thr (3), Ser (2), Lys (5), Gln (2), Pro (1), Leu (2), Val (2), Asn (2), Ala (2), Ile (1), His (1), Glu (1) b) Treatment with carboxypeptidase A liberates Gln c) The phenylthiohydantoin released by Edman degradation was PTH-Tyr d) Treatment with trypsin produces the following six peptides: Lys Gly-Gln Asn-Ala-Ile-Val-Lys Tyr-Gly-Gly-Phe-Met-Thr-Ser-Glu-Lys Asn-Ala-His-Lys Ser-Gln-Thr-Pro-Leu-Val-Thr-Leu-Phe-Lys e) Treatment with chymotrypsin produces the following three peptides: Lys-Asn-Ala-Ile-Val-Lys-Asn-Ala-His-Lys-Lys-Gly-Gln Tyr-Gly-Gly-Phe Met-Thr-Ser-Glu-Lys-Ser-Gln-Thr-Pro-Leu-Val-Thr-Leu-Phe ...
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midterm1_2004
USC, CHEM 432
Excerpt: ... s equal to that of the random coil. If Tm is measured to be 55 C, what is the value of H0 for the conformational change? Use the result from (A) as the change in standard state entropy. (iii) (11 points) When a mutation is introduced, the random coil state is not affected, but there are two possible orientations for 50 out of the 100 amino acid residues in the folded state. The equilibrium constant is measured at a range of temperature to determine H0 and S0 for the mutant. Three hypothetic ln (K) vs. 1/T plots are shown for the wild type and mutant protein. Based on information provided in (i) and (iii), which plot can be eliminated? Why? 2 Note: The arrow on the y-axis indicates increasing ln(K), and the arrow on the x-axis indicates increasing 1/T. 3 ...
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lecture 9
Texas Tech, ANSC 5311
Excerpt: ... 1. B. B. ruminicola, S. ruminantium, B. fibrisolvens, and S. bovis have all been shown to be proteolytic Proteases of ruminal bacteria seem to be cell-associated little proteolytic activity in cell-free ruminal fluid 1. 2. 3. 4. B. fibrisolvens can release proteases into the fluid Purified proteases from ruminal bacteria have not been isolated for study Both exopeptidase and endopeptidase activity have been identified Activity is of like that of various known types serine proteases, cysteine proteases, aspartic proteases, metalloproteases, and papain types have been identified Limited data suggest that proteolytic activity of different species may be synergistic Solubility of proteins is primarily determined by the proportion of hydrophobic residues on the exterior of the protein molecule a) Most proteins have hydrophilic amino acid residues on the exterior 5. C. Solubility of protein sources in ruminal fluid affects protease activity 1. b) 2. Heat and certain chemical treatments unfold the tertiar ...
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6.S-Catalytic
Minnesota, BIOSCI 6011
Excerpt: ... me intermediate, acid base catalysis, and a charge relay network (catalytic triad).Chymotrypsin cleaves peptide (amide) bonds on the amino side of bulky amino acid residues such as phenylalanine and methionine. Chymotrypsin is a serine protease. Its active site has a uniquely active serine hydroxyl group that can lose a proton and become anionic during the course catalysis. That property makes the active site serine residue highly susceptible to reaction with the reagent DIFP. This reaction produces a covalent product and inactivates the enzyme. The assay of chymotrypsin is accomplished using an artificial substrate that mimics peptides, but whose hydrolysis is easily measured. When the N-acetyl-L-phenylalanine p-nitrophenyl ester is hydrolyzed, a colored product, p-nitrophenylate is released. The rapid kinetic analysis of p-nitrophenylate release shows that there is a burst phase during the first round of hydrolysis followed by a steady state phase which last through many rounds of cleavage. This sug ...
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sp08%20First%20Exam
UCSD, BIBC 102
Excerpt: ... (E) If the R groups of the amino acid residues in positions 1,3,5, and 7 in a strand of this protein project to the exterior of the sheet plane, the R groups of the amino acid residues is positions 2,4, and 6 will project to the interior of the sheet plane (actually the interior of the barrel). 2. Which one of the following statements is blatantly false? (A) Km, the Michaelis constant, is the substrate concentration at which the initial reaction velocity, Vo, is half of Vmax, and the units of Km are therefore molar. (B) The initial velocity of an enzyme catalyzed reaction, Vo, is proportional to the total enzyme concentration, [E]T, regardless of the substrate concentration, [S]. (C) Enzymes increase the rate constant for the reaction they catalyze by lowering the activation free energy (G) for the reaction, and they accomplish this by selectively stabilizing the transition state structure of this reaction. (D) Vmax is proportional to the enzyme concentration and is the velocity attained when all enzym ...
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ms-1
UWO, CS 661
Excerpt: ... ids Residues Exact Mass of Amino Acid Residues in Proteins Gly Ala Gln Lys Glu G A Q K E 57.02150 71.03720 128.05860 128.09500 129.04270 Note: Leu (L) = Ile (I) = 113.08410 Amino Acid Table AA Codes Gly Ala Ser Pro Val Thr Cys Leu Ile Asn G A S P V T C L I N Mono. 57.021464 71.037114 87.032029 97.052764 99.068414 101.04768 103.00919 113.08406 113.08406 114.04293 I O N S O U R C E . C O M AA Codes Asp Gln Lys Glu Met His Phe Arg CMC Tyr Y D Q K E M H F R Mono. 115.02694 128.05858 128.09496 129.04259 131.04048 137.05891 147.06841 156.10111 161.01467 163.06333 Cysteine Proteins are often treated so that cysteine becomes carboxyamidomethyl cysteine (CamC) or Carboxymethyl (CmC) in order to break the disulphide bonds. CamC = 160.03 Mass of Peptides and Proteins Ala-Ser-Phe (ASF) tripeptide (MW 71.04+87.03+147.07+18.01)=323.15 More precisely: monoisotopic mass 323.1481 average mass 323.3490 In a mass spectrum Deconvolution adds all the isotopic peaks to the monoisotopic peak. So, t ...
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27_Lieb_Translation
UNC, BIOL 201
Excerpt: ... Lieb- Biology 202 Translation & Protein Structure I. Polypeptides Amino acids have a central (alpha) carbon atom attached to an amino group (NH2) a carboxyl group (COOH) a side chain (R, for reactive group). H HN R C H C O OH In a polypeptide, amino acids are linked by peptide bonds between the carboxyl group of one aa and the amino group of the next. H HN R C H C O OH + H HN R C H C O OH HR HN C H O H CN R C H C O OH + H2O Because this is a dehydration reaction (water is removed), we often refer to amino acid residues in a polypeptide. Just as nucleic acid strands have polarity (a 5' end and 3' end), so do polypeptides. They have an amino terminus and carboxy terminus. II. Levels of protein structure primary structure: sequence of amino acids in a polypeptide. Similarity in amino acid sequence can be used to find evolutionary relationships among proteins and to define families or conserved proteins. motifs or blocks are short regions of conserved sequence (and usually conserved function) that c ...
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Recitation__3_-_Simona
MIT, 7 7.05
Excerpt: ... 7.05 Section 05 TA: Simona Tescu Email: tescu@mit.edu RECTATION #3 02/27/2008 Covers lectures: 6, 7, 8 and 9 (Enzyme chemistry, catalysis, kinetics, DNA and RNA) Exam I is on Friday! Read online guidelines posted by Prof. Yaffe and come to the rev ...
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