This document discusses the different levels of protein structure: - The primary structure is the linear sequence of amino acids in the polypeptide chain. Hydrogen bonds form between amino acids, influencing secondary structure. - Secondary structure includes alpha helices, beta pleated sheets, and beta turns - regular patterns formed by hydrogen bonds in the primary structure. - Tertiary structure is the overall 3D shape of the folded polypeptide chain, influenced by interactions between amino acid side chains like hydrophobic interactions and disulfide bridges. - Quaternary structure involves multiple polypeptide subunits that combine via hydrogen bonds and van der Waals forces to form a single protein. Some proteins do not have quaternary

1. LEVELS OF PROTEIN
STRUCTURE
PRESENTED BY
OM PRAKASH SHAH
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2. TRANSLATION
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3. PRIMARY
STRUCTURE
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4. PRIMARY
STRUCTURE
 Proteins are made up of building blocks called Amino.
And there are 20 different types of amino Acids present
in our body.
 These amino acids are held togather by a covalent bond
known as Peptide Bond.
 These Amino Acids binded in a specific sequence by the
process called Translation to form a Poly-Peptide Chain.
 This specific sequence of Amino Acids in the
Polypeptide is called the Primary Structure.
 Each Amino Acids in the Primary Structure are also
Known as Residue.
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5. PRIMARY
STRUCTURE
 The Polypeptide Chain in a Protein Molecule has the ability to
form many Hydogen Bonds.
 This is because each one of the Amino Acids contains two types
of Functional Groups-
N-H - Group - Hydohen Bond Donor.
C=O - Group - Hydohen Bond Acceptor.
 This phenomena play an important role on the formation of
secondary structure of protein.
 It is also important to note that the Peptide Bond of the
polypeptide chain is Double Bond in nature i.e they cant rotate
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6. SECONDARY
STRUCTURE
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7. SECONDARY
STRUCTURE
 Once the primary structure of protein is formed, It begins to twist
and turn into regular patters that make up its secondary structure.
 These regular patterns include-
α-Helix.
β Plated Sheets.
β Turns.
Ω Loops.
 This twist and turns are formed as a result of the regular pattern of
the hydrogen bonds between NH and CO groups on the polypeptide
chain.
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8.  The Alpha Helix is the Twisted structure of polypeptide
chain.
 It contains the Back bone on inner portion of the chain and
on the outer side there are the side chain.
 This structure is formed as a results of bond formation
between the NH group and CO group.
ALPHA HELIX
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9.  The beta pleated sheet is polypeptide chains running along
side each other linked together by hydrogen bonds.
 It is called the pleated sheet because of the wave like
appearance.
 This allow to form more H-bonds in the Polypeptide and
thus resulting in more compact structure.
BETA PLATED SHEETS
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10.  Beta turns, also known as beta bends or tight turns, are a
type of secondary structure.
 Beta turns change the direction of the peptide backbone by
nearly 180°, allowing the peptide chain to fold back onto
itself
 These turns generally occur when the protein chain needs to
change direction in order to connect two other elements of
secondary structure.
 They are composed of Four Amino Acids and there is a H-
Bond between the first AA and the fourth AA.
BETA TURNS
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11. Tertiary Structure
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12.  The tertiary structure of a protein refers to the overall three-dimensional
arrangement of its polypeptide chain will take within its local environment.
 There are several factors / interaction between the amino acids that leads to
the formation of this structure,namely-
1. Hydrobhobic Interaction.
2. Di-sulphide Bridge.
3. Hydrogen Bond.
4. Hydrophillic Interaction.
5. Ionic Bond.
TERTIARY STRUCTURE
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13. TERTIARY STRUCTURE
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14.  The quaternary structure of a protein is formed when two or more polypeptide
(Subunit) bind togather to give a single protein having a specific function.
 Protein quaternary structure is the fourth (and highest) level of protein structure.
 Each of the subunits has its own primary, secondary, and tertiary structure.
 The subunits are held together by hydrogen bonds and van der Waals forces
between nonpolar side chains.
 Not all proteins have a quaternary structure since some proteins function as single
units.
 Depending upon the number of subunit these proteins are named as Monomer,
Dimer, Trimer, Tertramer........
QUATERNARY
STRUCTURE
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15. DOMAINS IN
PROTEIN
STRUCTURE
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16. DOMAINS
Domains are distinct functional and/or structural units
in a protein.
• It is a region of the protein's polypeptide chain that is self-
stabilizing and that folds independently from the rest.
• The independent folded regions are connected by a Hinge region.
• This hinge region arises when small AA like Glycine are found in a
repeated sequence in a poplypeptide chain.
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17. MOTIFS IN
PROTEIN
STRUCTURE
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18. • Two or more than two secondary structure (Super Secondary)
combine togather during protein folding to form MOTIF.
• It is a tertiary structure that arises by combing two or more than
two secodary structure.
• It provide function to a protein.
Motifs are super secondary structure in a polypeptide chain.
MOTIFS
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19. FOLDING OF
PROTEIN
STRUCTURE
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20. • It is the process by which the Primary Structure is converted into
Secondary Structure, the Secondary to Tertiary and Tertiary to
Quaternary Structure.
• There are two types of protein foldings that is observed
depending upon the timing of folding.
1. Co-Translational folding- Ocuurs while translation is going on.
2. After translation- Occurs after the Translation process is
completed.
Protein folding is the process by which a protein gets its 3-Dimentional structure
FOLDINGS
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21. VIDEO LINKS
1. Overview of Structure of protein.
2. Primary Structure of Protein.
3. Secondary Structure of protein.
4. Tertiary Structure of Protein.
5. Quaternay Structure of Protein.
6. Motifs and Domains.
7. Protein Foldings.
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22. THANK YOU
FOR LISTENING
DANDWASTH DHANYAWAAD
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