lecture notes: introduction to carbohydrates
TRANSCRIPT
Some Carbohydrate Functions
• Developmental processes• Protein localization• Regulation of activity• Cell-cell interactions• Structural integrity, e.g. cell walls• Phytohormones• Plant and animal defense• Prevention of desiccation (bacteria)• Adherence of bacteria to surfaces• Bacterial resistance to host defenses• Cell-cell recognition and signaling
Introduction to CarbohydratesBiochemistry
Garrett & GrishamChapter 7, p. 209-237
Cn (H2 O)n
C
CHOH
CH2OH
OCH2OH
( )n
Poly-hydroxy-ketone
C
CHOH
CH2OH
OH
( )n
Poly-hydroxy-aldehyde
Monosaccharides
C
CHOH
CH2OH
OH
C
CHOH
CHOH
OH
CHOH
CHOH
CH2OH
C
CHOH
CHOH
OH
CHOH
CH2OH
C
CHOH
CHOH
OH
CH2OH
12
3
12
3
1
23
12
34
5
65
4
4
Aldose family
C
CHOH
CHOH
CHOH
CH2OH
O
CH2OH
C
CHOH
CHOH
CH2OH
O
CH2OH
C
CHOH
CH2OH
O
CH2OH
C
CH2OH
O
CH2OH12
3
12
3
4
1
2
3
5
4
1
2
3
4
5
6
Ketose family
Stereo-isomerism
D-glyceraldehyde L-glyceraldehyde
1
32
C
CHOH
CH2OH
OH
CHO
HOHHOCH2
CHO
CH2OHH
CHO
OHHOCH2
H
CHO
CH2OHHOH
CHO
CH2OH
OHHCHO
CH2OH
HHO
HO
COH
HOCH
CH2OH
R S
D-glyceraldehyde
D-threose D-erythrose
D-lyxose D-xylose D-arabinose D-ribose
D-talose D-galactose D-idose D-gulose D-mannose D-glucose D-altrose D-allose
C
CHOH
CH2OH
OH
C
HCOH
HCOH
OH
HCOH
HCOH
CH2OH
C
HOCH
HCOH
OH
HCOHHCOH
CH2OH
C
HCOHHOCH
OH
HCOH
HCOH
CH2OH
CHOCH
HOCH
OH
HCOH
CH2OH
HCOH
COH
HCOH
HCOH
HOCH
HCOH
CH2OH
COH
HOCH
CH2OH
HCOH
HOCH
HCOH
COH
HCOH
HOCH
CH2OH
HCOH
HOCH
COH
HOCH
HOCH
HOCH
HCOH
CH2OH
HOCH
CH2OH
HCOH
HOCH
COH
HCOH
HOCH
HCOH
CH2OH
COH
HOCH
HCOH
HCOH
CH2OH
COH
HCOHHCOH
HCOH
CH2OH
COH
CH2OH
HCOH
HOCH
COH
HCOH
HCOH
CH2OH
COH
D-Aldoses
D-Ketoses
dihydroxyacetone
D-erythrulose
D-xylulose D-ribulose
D-tagatose D-sorbose D-fructose D-psicose
CH2OH
C
HCOH
HCOH
HCOH
CH2OH
O
CH2OH
C O
HOCH
CH2OH
HCOH
HCOH
CH2OH
C
HCOH
O
HOCH
CH2OH
HCOH
CH2OH
C O
HOCH
HCOH
CH2OH
HOCH
HOCH
CH2OH
HCOH
C
CH2OH
O
HCOH
HCOH
CH2OH
C O
CH2OH
HCOH
CH2OH
C O
CH2OH
CH2OH
C O
CH2OH
Hemi-acetal (ketal)
R CO
HO C R'
H
R C O
H
C R'
C
C
C
C
C
CH2OH
OH
H OH
HO H
H OH
H OH
C
C
C
C
C
CH2OH
H OH
HO H
H OH
H
H
O
OH C
C
C
C
C
CH2OH
H OH
HO H
H OH
H
HO
O
H
Anomers
α-D-glucose D-glucose β-D-glucose
HO
Haworth Structures
C
C
C
C
C
CH2OH
H OH
HO H
H OH
H
H
O
OH
OHOH
CH2OH
H
OHH
H
HO OH
H O
OH
CH2OH
OHHO OH
O
C
C
C
C
CH2OH
H CH2OH
HO H
H OH
H
O O
CH2OH
OH
H
HO
OH
HH
HOCH2 O
CH2OH
OH
HO
OH
HOCH2
O
Fischer
Haworth
pyran
furan
α-D-glucopyranose
β-D-fructofuranose
Conformations
OHOH
CH2OH
H
OHH
H
HO H
OHO
H
OH
H
OHH
HO
H
HOCH2OH
O
OH
H
OH
H
OH
HOH
H
CH2OH
H(e)
(a)4C1
1C4
envelope (E) twist (T)
4C14C1
Various Glycosyl Residues
O
OH
CH2OH
HO HO OH
O
OH
CH2OH
OH
HOOH
O
OH
COOH
OHHO
OH
O
OH
COOH
OH
HOOH CHOH
HCOH
CH2OH
NH COOH
OHH
HOH
H3CC
OO
OH
HO
OH
COOHH
H
HOCH
CH2OH
OH
OHHO
OHOH
D-Mannose D-Galactose D-Glucuronic acid
D-Galacturonic acid N-Acetylneuraminic acid(Sialic acid)
3-Deoxy-D-manno-2-octulosonic acid
myo-inositol
β-L-Rhamnose
O
H
OH
H
H3C
HOHO
OH6-deoxy-β-L-mannose
O
OH
CH2OH
HOHO
OH O
HOOHOH
HOHOCH2
O
HOOHOH
HOCH3 O
OH
CH3
HO
HO
OH
D-mannose L-mannose
O
OH
H
H
OHOH
H
OH
HCH3
HO
H
OH
OH
HH
HO
H
HO
H
CH2OH
β-D-Man
O
H
OH
H
H3C
HOHO
OH
Mutarotation
O
OH
CH2OH
HO
HO O
H
H
H+
O
OH
CH2OH
HO
HO
OHOH
OH
CH2OH
HO
HOC
O
H
H+
α βopen chain
Initial state 1
aqueous solution ofD-glucose with X g/ml and a specificrotation of +112.2o
Initial state 2
aqueous solution ofD-glucose with X g/ml and a specificrotation of +18.7o
Final state for both
equilibrium solutionwith a specificrotation of +18.7o
Some Reactions
C
HCOHHOCH
OH
HCOH
HCOH
CH2OH
CH2OH
HCOHHOCH
HCOH
HCOH
CH2OH
CH2OH
HCOHHOCH
HOCH
CH2OH
HCOH
C
HCOHHOCH
OH
HOCH
CH2OH
HCOH
COOH
HCOHHOCH
HCOH
HCOH
CH2OH
C
HCOHHOCH
HCOH
HC
CH2OH
O
O
C
HCOHHOCH
OH
HCOH
HCOH
COOH
COOH
HCOHHOCH
HCOH
HCOH
COOH
O
OH
CH2OH
OHHO OH
O
OH
CH2OH
OHHO OCH3
CH3OH
H+
H2OH+
Reduction
D-glucitol(sorbitol)
D-galactitol(dulcitol)
D-gluconic acid D-gluconlactone D-glucuronic acid D-glucaric acid
Oxidation
Glycoside formation
methyl-α-D-glucose (methyl-α-D-glucopyranoside)
O
OH
CH2OH
OH
HO
OH
O
OH
CH2OH
OHHO OH
O
OH
CH2OH
OHOH
OHO
OH
CH2OH
OH
O
OHOCH2
HO
HOCH2OH
O
OH
CH2OH
OHHO O
O
OH
CH2OH
OHHO
OO
CH2OH
H
HO
OH
HH
HOCH2
Oligosaccharides
A B4-O-β-galactopyranosyl-α-D-glucopyranose(lactose)
2-O-α-D-glucopyranosyl-β-D-fructofuranoside(sucrose)
A B
BB
B
A
A
A
Adenosine
O
HOOH
HOCH2
NH2
N
N
N
N
N-Glycosidic bond
PolysaccharidesO
OH
CH2OH
OH
OOO
OH
CH2OH
OH
O
O
OH
CH2OH
OH
O
O
OH
CH2OH
OH
O
OCH2OH
NH
OHO
O O
OH
COOH
OH
O
CCH3O
OCH2OH
NH
OHO
O
OH
COOH
OH
O
CCH3O
O
OH
CH2OH
OHOO
O
OH
CH2OH
OHO
O
OH
CH2
OHO
O
O
OH
CH2OH
OHO
O
OH
CH2OH
OH
O
OCH2OSO3
-
NH
O
CCH3O
OH
O
OH
COO-
OH
O
OCH2OSO3
-
NH
O
SO3-
OHO O
OSO3-
COO-
OH
O
Cellulose (a homopolysaccharide)
Starch
Hyaluronic acid(a heteropolysaccharide)
Heparan sulfate
D-Glc + ATP D-Glc-6-P + ADP
D-Glc-6-P D-Glc-1-P
D-Glc-1-P + UTP UDP-Glc + PPi
2Pi
“Activated” Sugar Donors
O
HOOH
CH2
O
HN
N
O
O
P O-O
OP
O
-O
O
O
OH
CH2OH
OH
HO
NDP-sugar pyrophosphorylase(UDP-glucose pyrophosphorylase)
UDP-Glc
UDP-Gal
UDP-GlcA
UDP-GalA
GDP-Man
GDP-Fuc
UDP-GlcNAc
dTDP-Glc
ADP-Glc
dTDP-Rha
CMP-Kdo
CMP-NeuNAc
ADP-Hep
Sugar Nucleotide Biosynthesis
UDP-Glc Gal-1-P Glc-1-PUDP-Gal+ +
UDP-Glc UDP-GlcA
NAD+ NADPH2 2
UDP-GlcA UDP-GalA
dTDP-D-Glc dTDP-L-Rha
GDP-D-Man GDP-L-Fuc
galactose 1-phosphate uridylyltransferase (galT)
UDP-glucose dehyrogenase
H2O + + 2H+
UDP-glucuronic acid 4-epimerase
UDP-Glucose 4-Epimerase(galE)
UDP-Glc UDP-GalO
OH
CH2OH
OHUDPHO
O
OH
CH2OH
OHUDP
O
NADP+
NADPH
NADPH
NADP+
O
OH
CH2OH
OHUDP
HO
dTDP-L-Rhamnose Biosynthesis
dTDP-D-Glc
dTDP-4-dehydro-6-deoxy-D-Glc
dTDP-4-dehydro-6-deoxy-L-Man
H2OdTDP-glucose 4,6-dehydratase (rfbB)
dTDP-4-dehydrorhamnose 3,5-epimerase (rfbC)
NADPH
NADP+
dTDP-4-dehydrorhamnose reductase (rfbD)
dTDP-L-Rha
dTDP-Rhamnose Biosynthesis:Reaction Mechanism
O
OH
CH2
OHO
H
OH
H
H O dTDPEnz
NAD+
B:
O
OH
CH2
OH
OH
HOO dTDP
EnzNADH
B:
O
OH
CH2
OH
OH
-OO dTDP
O
OH
CH2
OH
OH
OO dTDP
-
+HB
O
OH
CH2
OH
OO dTDP
Enz
NAD
B:
:H
O
OH
CH3
OH
-OO dTDP
+HBO
OH
CH3
OH
OO dTDP
H
O
OH
CH3
OHO dTDP
HHO
O
OH
CH3
OH
OO dTDP
HO
OH
CH3
OHO dTDP
HOO
OH
CH3
OH
OO dTDP
H
O
OH
CH3
OHO dTDP
HHO
dTDPdTDP--glucose 4,6glucose 4,6--dehydratasedehydratasedTDPdTDP--44--dehydrorhamnose dehydrorhamnose 3,53,5--epimeraseepimerasedTDPdTDP--44--dehydrorhamnosedehydrorhamnosereductasereductase
Biosynthesis of CMP-NeuNAc and -Kdo
CMP-NeuNAc CMP-KdoUDP-GlcNAc
UDP-ManNAc
ManNAc
NeuNAc
CMP-NeuNAc
UDP-GlcNAc 2-epimerase
(UDP-ManNAc hydrolase)
UDP
pyr.NeuNAc lyase
PEP
Kdo-8-P
Ara-5-P
Pi
Kdo-8-P aldolase (kdsA)
Kdo-8-P phosphatase
Pi
KdoCTP
PPi
Kdo cytidyltransferase(kdsB)
CMP-KdoCTP
PPi
NeuNAc cytidyltransferase
OHOH
HOCH
H
HHH
HO
O
COOH
P
O
O-
O CH2
OHOH
O
O N
HN
CH2OH Kdo forms a highenergy ketal bondmaking the CMPa very good leavinggroup.
Glycosyl Transferase ReactionsO
HOH
CH2OH
H
OHH
H
HO O UDP
OHOH
CH2OH
H
OH
H
H
HO O
H
P O P O( )n
OHOH
CH2OH
H
OHH
H
HO O P O P O Rib U
O O
O- O-
:X R
OHOH
CH2OH
H
OHH
H
HO
X R
+P O P O Rib U
O O
O- O-
-O
OHOH
CH2OH
H
OHH
H
HO
B Enz
OHOH
CH2OH
H
OHH
H
HO
B Enz
+ P O P O Rib U
O O
O- O-
-O
OHOH
CH2OH
H
OHH
H
HO O P O P O Rib U
O O
O- O-
:X R
OHOH
CH2OH
H
OHH
H
HO X R
:B Enz
+ :B Enz
UDP-Glc Man-DolFormation of β-linkages Formation of α-linkages
:X-R where :X can be a hydroxyl, amine, amide, phosphate,and R can be a sugar, lipid, protein, etc.