MCB 450 1st Edition Lecture 6 Outline of Last Lecture I. Tissue & Cell Fractionationa. CentrifugationII. Protein Purificationa. Chromatographyb. ElectrophoresisIII. AntibodiesIV. Peptide fragmentation & sequencinga. Edman DegradationV. Analysis of Protein Structure by X-ray CrystallographyOutline of Current Lecture I. MonosaccharidesII. Glycosidic bondsIII. PolysaccharidesCurrent LectureWhy do we need to use X-ray diffraction?-Any resolution that we get is comparable to wavelength-The problem we run into when viewing a protein is the wavelength of visible light is 4,000 - 7,000-To look at them this way we need a protein crystalGrowing protein crystals-We consider crystals large when they are about 0.5mm-3/4 of the crystal volume is actually filled with water moleculesoThis environment is very similar to the environment it will be in the cell-If a protein is well ordered then they will form parallel planes-The reflection (mirror-like) will show density, etc. and information we are wanting to find out about the protein Analogy between X-ray diffraction and light microscopy-Similar to light microscopyGenerating an electron density map-From the diffraction pattern can create a structural modelX-ray structures determined to a certain A resolution-As Angstroms decrease, resolution increaseso5.0A is a lower resolution than 1.5A-More structures are visible at 1.5AThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.Carbohydrates-Carbs are most abundant biomolecules on the planet-Play many rolesClasses of saccharides-Oligosaccharides -- 2-20 monosaccharides joined together by glycosidic bonds-Polysaccharides -- chains of 20-1000 monosaccharides -Can get very different structures depending on how they are connectedMonosaccharides-1-Simplest monosaccharides have 3 carbonsoCarbons continue growing by adding H-C-OH groupsMonosaccharides have asymmetric centers-All monosaccharides (except dihydroxylacetone) have one or more asymmetric carbon (chiral centers)D and L configurations of monosaccharides-In determining D and L configurations look at the chiral carbon that is furthest from the carbonyl-D and L configurations -- exam questions-Carbonyl carbon is labeled carbon 1-Aldopentose -- 8 possibleo4 D and 4 LEpimers-Epimer -- 2 sugars that differ only in the configuration around one carbonFormation of 2 cyclic forms of glucose-Haworth perspective-Pyranose form-Slide 6-22 -- popular exercises for homework and examsInterconversion between anomers-Mutarotation -- when alpha and beta anomers introconvert-D-glucose (linear form) -- has the chemical properties of an aldehydeConformations of pyranoses-Subsituents on the ring have two orientations oAxial = up or downoEquatorial = left or right-Chair form relatively rare unless a bulky structure forces it into that formDefinitions - 1 & 2-Stereoisomers vs. enantiomers-Know definitionsMonosaccharide derivatives-In biology there are sugar derivativesoBeta-2-deoxy-D-riboseoFucose -- in seaweedoGlucosamineoGlucouronateoGluconateoSorbitol-Know shorthand of derivativesFormation of glycosides-Methanol is a simple example-Glycogen  heavily hydrated-Change from alpha to beta and get cellulose-Cellulose has very little water oHumans can't digest