Monosaccharides

Glc

Glucose (3)

Galactose (3)

Man

Mannose (3)

GlcNAc

N-acetylglucosamine (short)

(GalNAc)

N-acetyl galactosamine (short)

Fuc

L-Fucose (short)

Sia, Neu5Ac

Sialic acid ( short)

Xyl

Xylose (3)

GlcA

Glucuronic Acid short

Circle

Hexoses shape

Star

Pentose shape

Square

N-acetylhexosamine shape

Diamond

Acidic sugar shape

Galactose

Glucose

Mannose

hexoses: [3]

1. sialic acid

2. glucuronic acid

Acidic sugars (2)

Xylose

pentose sugar [1]

Triangle

Deoxysugar shape

galactose shape

glucose shape

mannose shape

xylose shape

Fucose shape

N-acetyl galactosamine shape

N-acetyl glucosamine shape

Sialic acid shape

Glucuronic acid shape

amino aicds

fatty acids

carbohydrates

nucleobases

major classes of biological molecules [4]

1. carbon

2. hydrogen

3. oxygen

Carbohydrates are organic molecules containing:

multiple -OH (hydroxyl) groups

Carbohydrates often have this group, making it hydrophilic

oligosaccharide

short sugar chain

Polysaccharide

Carbohydrate with many sugar units

1. glucose

2. glycogen

3. starch

Carbs involved in energy and storage [3]

1. cellulose

2. chitin

carbs for structural support [2]

1. ribose

2. deoxyribose

carbs part of nucleic acids [2]

Glycosaminoglycans in connective tissues

carbs involved in lubrication

Carbohydrates

broad class of molecules including simple sugars and complex carbohydrate structures

Glycans

sugar based structures that may be free or attached to other molecules

Glycoconjugate

Molecule in which glycans are covalently attached to another component, such as a protein or lipid

Glycobiology

study of glycan structures, their synthesis, and their biological functions

Glycosidic bonds

bonds connect monosaccharides

D form

chiral molecule that is biologically relevant

alpha and beta

two possible conformations at the anomeric carbon

chair to accomodate bond angles and minimize strain

conformer that is most stable

equitorial

substitutions are less sterically hindered in this position

Connects through oxygen to another sugar

In typical sugar-sugar linkage, the anomeric carbon of one sugar is connected to what of the other?

Condensation reaction (removal of water molecule)

reaction that connects sugars

1. starch

2. cellulose

two carbohydrates both made of glucose with different functions

Alpha

linkages in starch

Beta

linkages in cellulose

Glycosyltransferases

enzyme catalyzes the formation of glycosidic bonds by transferring sugars from activated donors

Activate sugars by attaching them to nucleotides, creating nucleotide sugars that enzymes can use to build glycosidic bonds

How do cells join monosaccharides together?

They have different glycosyltransferase activities

one reason people have different blood-group antigens

Glycoside hydrolases

catalyses hydrolysis of glycosidic bonds

glycoprotein

glycan attached to protein

proteoglycan

glycan attached to protein core

Glycolipid

glycan attached to lipid

GlycoRNA

Glycan attached to RNA

1. recognition

2. signalling

3. protein stability

major functions of glycoproteins [3]

1. hydration

2. mechanical support

3. signalling

Proteoglycan major functions [3]

short, branched

Carbohydrate chains of glycoproteins are often:

long, repeating GAG

Carbohydrate chains of proteoglycans are typically:

The extracellular environment

Carbohydrate portions of glycolipids typically face where?

Blood type A

Blood type needs glycosyltransferase that adds N-acetylgalactosamine

Type B

Blood type that has a different glycosyltransferase that adds galactose instead

no functional A or B glycosyltransferase so additional sugar is not attached

Blood type O lacks what

Glycan structure

How does influenza recognize a host cell?

Hemagglutinin

Protein on influenza surface that binds to glycans that contain sialic acid