INTRODUCTION CONCEPT AND TERMINOLOGIES ABOUT CONFORMATIONS DIHEDRAL ANGLES AND A MAP OF FAVORED CONFORMATIONS   CLASSES OF CONFORMATIONS WITH EXAMPLES ORDERED CONFORMATION DISORDERED CONFORMATION IMPORTANCE OF CONFORMATIONAL PROPERTIES CONCLUSIONS REFERENCES

1. Polysaccharides
Experimental studies on
conformational properties
By
KAUSHAL KUMAR SAHU
Assistant Professor (Ad Hoc)
Department of Biotechnology
Govt. Digvijay Autonomous P. G. College
Raj-Nandgaon ( C. G. )

2. SYNOPSIS
 INTRODUCTION
 CONCEPT AND TERMINOLOGIES ABOUT CONFORMATIONS
 DIHEDRAL ANGLES AND A MAP OF FAVORED CONFORMATIONS
 CLASSES OF CONFORMATIONS WITH EXAMPLES
ORDERED CONFORMATION
DISORDERED CONFORMATION
 IMPORTANCE OF CONFORMATIONAL PROPERTIES
 CONCLUSIONS
 REFERENCES

3. INTRODUCTION
 Carbohydrates or saccharides (Greek: sakcharon, sugar) are
the most abundant biological molecules.
 Polysaccharides, the polymers of sugars, have storage and
structural role.
 In order to understand the molecular basis of
polysaccharides in relation to their functional
properties, it is important to appreciate higher levels of
structures of polysaccharides based on the shape or
conformation of these polymers in nature.

4. CONCEPTS AND TERMINOLOGIES
•BASIC TERMS ABOUT STRUCTURES
ENANTIOMERS ; The enantiomers are mirror images of each other.
The total number of isomers can be determined by using Vant Hoff’s rule (2n ).

5. EPIMERS :
 SUGARS THAT DIFFER ONLY BY THE
STEREOCHEMISTRY AT A SINGLE CARBON (NOT
ANOMERIC CARBON ) ARE CALLED EPIMERS.

6. LINEAR AND CYCLIC FORM

7. ANOMERS:
O
OH
OH
OH
OH
CH2OH
-D glucopyranose
O
OH
OH
OH
OH
CH2OH
-D glucopyranose
MUTAROTATION:
- Mutarotation is the interconversion of the  and  anomer

8. CONCEPT OF DIFFERENT CONFORMATIONS
 The relative orientations between any two
participating monosaccharide units are defined by two
or three torsion angles around the glycosidic bonds.
 The conformation of any individual monosaccharide is
relatively fixed in the polysaccharide chain, however,
the sugar residues linked through glycosidic linkage
will rotate around the glycosidic bond and often tend
to adopt an orientation of lower or lowest energies.

9.  Three dimensional
structure can be
described in terms of
dihedral angles ф and ψ
about glycosidic bond.
DIHEDRAL ANGLES AND A MAP OF FAVORED
CONFORMATIONS

10. A map of favored conformations for oligosaccharides and polysaccharides.
• red dot-least f favored conformation,
• blue dot -most favored conformation.

11. CLASSES OF CONFORMATION OF POLYSACCHARIDES
 Ordered conformation
Ribbon-like type conformation
Hollow helix like conformation
Periodic type conformation
 Disordered conformation
Random coiling

12. Cellulose
cellulose
Cellulose
microfibrils in a
plant cell wall

13. Starch
Suspensions of amylose in
water adopt a helical conformation.
A model of a segment of amylose

14. (a) Starch:
a plant polysaccharide
(b) Glycogen:
an animal polysaccharide
Chloroplast
Starch granules
Mitochondria
Glycogen granules
Amylose
Amylopectin
Glycogen

15. The favored conformation of
agarose in water is a double
helix
AGAROSE

16. DISORDERED CONFORMATION
 ALGINATE
Like cellulose, chitin, mannan, and poly(D-
mannuronate) form extended ribbons and pack
together efficiently, taking
advantage of multiple hydrogen bonds.
Poly(_-L-guluronate) strands dimerize in the
presence of Ca2_, forming a structure
known as an “egg carton.”

17. IMPORTANCE OF CONFORMATIONAL PROPERTIES
 In storage
 In protection
 In laboratories
 In transport

18. CONCLUSIONS
• Polymers with  glucose are helical.
• Polymers with  glucose are straight.
• In straight structures, H atoms on one strand can bond
with OH groups on other strands.
• There is direct relationship between the three-
dimensional structures of oligosaccharides and
polysaccharides and their biological properties .
• The overall conformation of an oligosaccharide
depends primarily on the orientation of the torsion
angles (ф and ψ) between glycosyl residues.

19. REFERENCES
 LEHNINGER PRINCIPLE OF BIOCHEMISTRY BY
DAVID L. NELSON AND MICHAEL M. COX -5TH
EDITION.
 BIOCHEMISTER BY GARRET AND GRISHAM .
 BIOCHEMISTRY BY VOET AND VOET.