Carbohydrates CH339K

What Makes a Carbo a Carbo? Overall formula Where n ≥ 3 Etymology: From their general formula C n (H 2 O) n ; they were once thought to be hydrates of carbon.

Simplest Carbos: N=3 2 Tautomers Tautomers are isomers of organic compounds that readily interconvert by a chemical reaction called tautomerization. (Wikipedia)

Glyceraldehyde exists as a pair of enantiomers Enantiomers are non-superimposable mirror images Vertical bonds go into the plane of the projection Horizontal bonds emerge from the plane of projection

R-S Nomenclature (for the Organic guys)

With n > 3, you can form diastereomers Diastereomers are stereoisomers that are not mirror images

Hemiacetals and Hemiketals An aldehyde or a ketone can react wth an alcohol

Ring formation

Ring formation in a ketose

Anomers Differ at the hemiacetal or hemiketal carbon  -D-Glucose  -D-Glucose

Furanoses and Pyranoses

Multiple possible rings in a C 6 -Ketose

Multiple Possible Rings in a C 5 -Aldose

Ring pucker

Epimers Differ at only one carbon, but not the anomeric carbon

Sugar Derivatives -2H +,e - +H 2 O aldonolactoneAldonic acid Alduronic acid Amino sugar Substituted Amino sugar Cu 2+ +NH 3, -H 2 O Acetic anhydride

Sugar Derivatives

Glycosides Glycoside: Any of a group of organic compounds that yield a sugar and one or more nonsugar substances on hydrolysis.

Natural Glycosides Amygdalin is a poison found in the seeds of bitter almonds. It releases cyanide upon hydrolysis.

Amygdalin is also known as Laetrile or “Vitamin B17,” a quack (excuse me, “alternative”) cancer treatment.

Natural Glycosides Digitoxin is used as a heart stimulant in medicine; related componds are used as poisons in murder mysteries

Polymerization

Activation – couple to UDP

Disaccharides

Storage Polysacharides

amylopectin

Amylose Structure

Iodine Test for Starch – Molecular Basis I 2 + I -  I 3

Amylopectin:  -1,4 +  -1,6

Glycogen :  -1,4 +  -1,6 Glycogen in liver cells – stained with carmin

Storage Polysaccharides PolysaccharideLinkageBranchingSize (residues) Amylose  -1,4 unbranchedUp to 5,000 Amylopectin  -1,4 and  -1, residuesUp to 1,000,000 Glycogen  -1,4 and  -1, residuesUp to 50,000

Structural Polysaccharides

Cellulose

Cellulose complexes β(1-4) linkages form flat sheets analogous to β-sheets in proteins multiple hydrogen bonds between strands.

Chitin

Insect cuticles

Self-Nonself Recognition – Blood Groups

Bacterial Cell Walls Gram -Gram + Staphylococcus aureusEscherischia coli

Bacterial Cell Walls Gram -Gram +

Bacterial Cell Walls – another view

Peptidoglycan Components E. coliS. aureus

What the heck is diaminopimelate? Lysine with an extra carboxyl attached to C .

Transpeptidase cross-links the individual chains Gram -Gram +

Cross Linking E. ColiS. aureus

Spore formation Figure 1. Stages of sporulation. (A) Stage 0/I, (B) stage II, (C) stage III, (D) stage IV, (E) released spore. The hatched line around the spore in panels D and E is the coat. From: Cell. Mol. Life Sci. 59 (2002)

Bacillus anthracis

Do not try this at home!!!!! 1.It will not work as shown 2.You will die 3.Everyone you know will go to Gitmo Production

Delivery The M lb biological cluster bomb, which held 108 of the M114 bombs. Photograph: Chemical and Biological Defense Command Historical Research and Response Team, Aberdeen Proving Ground, Md.

Pilot anthrax plant at Ft. Detrick, MD (shut down in 1969) Al Hakam “Single-Cell Protein” Plant (demolished under UN supervision, 1996)

Whoopsie! 1979 – Sverdvlosk 66 people die Aerosol plume from “Military Compound 19” Somebody left the vent to the outside open.

 -Lactams This carbon forms covalent bond with active-site serine on transpeptidase enzyme

Glycosaminoglycans Aka Mucopolysaccharides - Unbranched polysaccharides - Repeating disaccharide - Hexose linked to aminohexose - Typically with many negative charges -Acidic -Slimy

Proteoglycans Cell surface or extracellular matrix Glycosaminoglycan(s) bound to core protein Noncovalent attachments to help bind extracellular matrix

Disease Deficient enzyme Accumulated products SymptomsIncidence Hurler syndromeα-L-iduronidase Heparan sulfateMental retardation 1 in Dermatan sulfateMicrognathia Coarse facies Macroglossia Retinal degeneration Corneal clouding Cardiomyopathy Hepatosplenomegal y Disease from Failure to Metabolize Glycosaminoglycans (One example of many)

Proteoglycan - Photo

Glycoproteins

Glycoprotein Functions FunctionGlycoproteins Structural moleculeCollagens Lubricant and protective agentMucins Transport moleculeTransferrin, ceruloplasmin Immunologic moleculeImmunoglobins, histocompatibility antigens Hormone Chorionoic gonadotropin, thyroid-stimulating hormone (TSH) EnzymeVarious, eg, alkaline phosphatase Cell attachment-recognition site Various proteins involved in cell-cell (eg, sperm-oocyte), virus-cell, bacterium-cell, and hormone cell interactions AntifreezeCertain plasma proteins of coldwater fish Interact with specific carbohydratesLectins, selectins (cell adhesion lectins), antibodies ReceptorVarious proteins involved in hormone and drug action Affect folding of certain proteinsCalnexin, calreticulin Regulation of developmentNotch and its analogs, key proteins in development Hemostasis (and thrombosis) Specific glycoproteins on the surface membranes of platelets

N-Linked Glycosylation All eukaryotes make N-linked glycoproteins Usually Cotranslational Consensus sequence Asn – X – Ser/Thr Usually when there’s an accessible loop in the folding protein structure

N-Linked Glycosylation (cont.) Core oligosaccharide synthesized on cytoplasmic side of ER Attached to dolichol in ER membrane Core oligo transferred to lumen of ER Core oligo transferred to protein Further processing occurs in ER / Golgi

N-Linked Glycosylation

O-Linked Glycosylation True posttranslational modification No oligo precursor Frequently starts with GalNAc Secretory cells Zona pellucida around mammalian eggs Hematopoeisis Inflammatory response Common (not universal!!) core

Frozen Fish (Not!) Chaenocephalus aceratus