Configuration and conformers of biomolecules

Configuration and conformers of biomolecules like carbohydrates and proteins

1. Configuration & Conformers OF biomolecules Presented By- ANSHIKA BANSAL BSc Hons DEI, Agra 1

2. CONTENTS- INTRODUCTION NEED TO STUDY DIFFERENT CONCEPTS- c is –trans concept Relative configuration e rythros-threos concept D-L concept (+) & (-) enantiomeres Absolute configuration (R-S concept) 2

3. INTRODUCTION Configuration - Configuration is permanent geometry refers to spatial arrangement of bonds can be changed only by breaking bonds Example : L- & D and R- & S- configurations CONFORMERS- Conformation is the spatial arrangement of atoms in a molecule It can be changed without breaking bonds. Example - rotation about single bonds produce the cis -trans, and E-Z conformations  3

4. Need to study To study the 3D structure of biomolecules systematically To understand the physical and chemical nature of biomolecules 4

5. Different concepts for configuration 5

6. 1) CIS-TRANS CONCEPT Showed by double bond containing compounds Same side- cis Opposite side- trans 6

7. Examples- In amino acids chain In lipids 7

8. 2) ERYTHROS-THREOS CONCEPT-when 2 chiral carbon is present 8

9. EXAMPLE- in carbohydrates 9

10. 3) D-L CONCEPT= relative confifuration L isomers have the hydroxy group attached to the left side of the asymmetric carbon furthest from the carbonyl while D isomers have the hydroxy group on the right side . NOTE- Naturally occurring sugars are D isomers .  Only L form of amino acids are found in proteins 10

11. Example- In carbohydrates In amino acids 11

12. 4) (+) and (-) enantiomers (+) enantiomers rotate plane-polarized light clockwise (also called dextrorotary, abbreviated  d ) while (-) enantiomers rotate it counter-clockwise (levorotary, or  l ). Measured by polarimeter 12

13. 5) R-S concept rules- Assign sequence priorities to the four substituents by looking at the atoms attached directly to the chiral center. 1 .   The higher the atomic number of the immediate substituent atom, the higher the priority. 2.   If two substituents have the same immediate substituent atom, evaluate atoms progressively further away from the chiral center until a difference is found. 3.   If double or triple bonded groups are encountered as substituents, they are treated as an equivalent set of single-bonded atoms. 13

14. examples R(rectus = right) S(sinister = left) 14

15. CONFORMERS OF BIOMOLECULES 15

16. Conformers of proteins 16

17. PRIMARY STRUCTURE- 17

18. SECONDARY STRUCTURES 18 α -helix β-pleated

19. Tertionary structure 19

20. Quadanary structure 20

21. Conformer of nucleic acid 21

22. 22

23. THANK YOU 23