Carbohydrates CH 339 K What Makes a Carbo

Carbohydrates CH 339 K

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

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

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

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 a-D-Glucose b-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 +H 2 O -2 H+, e- Cu 2+ aldonolactone Aldonic acid +NH 3, -H 2 O Acetic anhydride Alduronic acid Amino sugar Substituted Amino sugar

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 B 17, ” 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: a-1, 4 + a-1, 6

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

Storage Polysaccharides Polysaccharide Linkage Branching Size (residues) Amylose a-1, 4 unbranched Up to 5, 000 Amylopectin a-1, 4 and a-1, 6 25 -30 residues Up to 1, 000 Glycogen a-1, 4 and a-1, 6 8 -12 residues Up 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 + Staphylococcus aureus Gram - Escherischia coli

Bacterial Cell Walls Gram - Gram +

Bacterial Cell Walls – another view

Peptidoglycan Components E. coli S. aureus

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

Transpeptidase cross-links the individual chains Gram - Gram +

Cross Linking E. Coli S. 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

Production 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

Delivery The M 33 500 -lb biological cluster bomb, which held 108 of the M 114 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.

b-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 from Failure to Metabolize Glycosaminoglycans (One example of many) Disease Hurler syndrome Deficient enzyme Accumulated products α-L-iduronidase Heparan sulfate Dermatan sulfate Symptoms Incidence Mental retardation 1 in 100. 000 Micrognathia Coarse facies Macroglossia Retinal degeneration Corneal clouding Cardiomyopathy Hepatosplenomegal y

Proteoglycan - Photo

Glycoproteins

Glycoprotein Functions Function Glycoproteins Structural molecule Collagens Lubricant and protective agent Mucins Transport molecule Transferrin, ceruloplasmin Immunologic molecule Immunoglobins, histocompatibility antigens Hormone Chorionoic gonadotropin, thyroid-stimulating hormone (TSH) Enzyme Various, eg, alkaline phosphatase Cell attachment-recognition site Various proteins involved in cell-cell (eg, sperm-oocyte), virus-cell, bacterium-cell, and hormone cell interactions Antifreeze Certain plasma proteins of coldwater fish Interact with specific carbohydrates Lectins, selectins (cell adhesion lectins), antibodies Receptor Various proteins involved in hormone and drug action Affect folding of certain proteins Calnexin, calreticulin Regulation of development Notch 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 Gal. NAc Secretory cells Zona pellucida around mammalian eggs Hematopoeisis Inflammatory response Common (not universal!!) core

Frozen Fish (Not!) Chaenocephalus aceratus