The document discusses the various types of secondary structure and super secondary structure found in proteins, including alpha helices, beta sheets, and motifs formed from combinations of these structures. It describes the structural characteristics of each type of secondary structure and how they are formed through hydrogen bonding patterns. Super secondary structures are folding patterns of secondary structures that form functional protein domains.
types of secondary structure and super secondary structure of protein
1. TYPES OF SECONDARY STRUCTURE &
SUPER SECONDARY STRUCTURE OF
PROTEIN
Presented by:
LEO PRABHA. A
1st year MSc Biotechnology
Dayananda Sagar University
Guided by:
Dr. ROSHAN SIR
Assistant professor
Dayananda Sagar University
MSc. Biotechnology 1st semester/ seminar session 2021
4. SECONDARY STRUCTURE
•Local spatial arrangement
•Dihedral angle, phi and psi
•Most prominent are α helix and β sheets
•Stable
•Consist of : - α- helix
- β- pleated sheets
- Non repetitive structures
- Super secondary structures
MSc. Biotechnology 1st semester/ seminar session 2021
FIG. 6-4 Torsion angles of
the polypeptide backbone
(Pg no: 134, Voet & Voet)
5. ALPHA HELIX
•Right handed
•Spiral structure
•Tightly packed, coiled
•Side chain extended outwards
•3.6 residues per turn, 5.4A° pitch
•Phi- -57° & psi- -47°
•Hydrogen bond stabilizing factor, 3H bond per
turn
•Ex α keratin , found in skin, hair and nails
MSc. Biotechnology 1st semester/ seminar session 2021
FIGURE 5–2 Orientation of the
main chain atoms of a peptide
about the axis of an α helix.
Pg no: 103, Harpers illustrated
Biochemistry
6. FIGURE 4–4 Models of the helix, showing different aspects of its structure. (a) Ball-and-stick model showing the intrachain
hydrogen bonds. The repeat unit is a single turn of the helix, 3.6 residues. (b) The helix viewed from one end, looking down the
longitudinal axis. (c) As this space-filling model shows, the atoms in the center of the helix are in very close contact.
( Pg no : 120, Leininger)
MSc. Biotechnology 1st semester/ seminar session 2021
8. BETA SHEETS
•2/more polypeptides line up side by side
•Zig-zag arrangement of chain
•Βeta strand is extended
•H bond intra chain
•2 residue per turn
•Stabilized by H bond between carbonyl & amide group
•R- group protrude from zig-zag in opposite direction
•Consist of - Parallel
- Anti parallel
MSc. Biotechnology 1st semester/ seminar session 2021
FIG. 6-10 Pleated
appearance of a 𝛃
sheet (Pg no: 139,
Voet & Voet)
9. BETA SHEETS
•Parallel : -H bond chain extended in same direction
- amino & carbonyl (same)
•Anti Parallel : -H bond extended in opp direction
- amino & carbonyl (opp)
Fig: 6.9 beta
sheets (Pg
no: 138
Voet & voet)
MSc. Biotechnology 1st semester/ seminar session 2021
10. SUPER SECONDARY STRUCTURE
• Folding pattern of secondary structure (Motifs)
• βαβ motif
• β hairpin motif
• αα motif
• β barrel
• αβ barrel
•Greek key motif
MSc. Biotechnology 1st semester/ seminar session 2021
FIG. 6-28 Schematic diagrams of super secondary structures. (a) βαβ motif, (b)
β hairpin motif, (c) αα motif, and (d) Greek key motif, showing how it is
constructed from a folded-over β hairpin. (Pg no: 151 Voet & Voet)
11. DOMAIN
• Jane Richardson
•Large polypeptide
•Binding of substrate
•Modular protein
•Combinations of super secondary elements
•Small globular protein
MSc. Biotechnology 1st semester/ seminar session 2021
12. CONCLUSION
• important roles in protein structure & protein folding
• used to predict tertiary structure
• determine the pattern of hydrogen bonding
MSc. Biotechnology 1st semester/ seminar session 2021
13. REFERENCE
• Voet & Voet , Fundamental of biochemistry 5th edition.
• David L. Nelson & Michael M. Cox ,Principle of biochemistry, 6th edition
• David A. Bender & Victor W ,Harpers illustrated biochemistry, 31st edition
MSc. Biotechnology 1st semester/ seminar session 2021
