Chapter 4:The tertiary structure of proteins'

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Chapter 4 The tertiary structure of proteins.

• Definition of tertiary structure.
• Hydrophobic interactions
• Disulfide bonds.

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1. Definition
Tertiary structure General shape or conformation
of a polypeptide chain or how the protein
folds in space. The gene determines the primary
structure. Primary structure determines
secondary, tertiary and quaternary structure. Th
e conformation of a protein determines its
activity.
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Heme
Prosthetic group
Myoglobin
Globular proteins
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Plastocyanin
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3. Hydrophobic interactions.
What types of bonds or forces are involved in
tertiary structure formation. Most important
hydrophobic interaction Next disulfide
bonds Also occur. Charge interactions, hydrogen
bonds although less important.
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Tertiary structure
Side chains are involved
The most important interactions are
hydrophobic. Nonpolar (hydrophobic residues
inside Polar (hydrophilic) residues outside
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Which residues will be on the inside?
OH
COO- CH2
CH3 CH2 -NH
CH CO NH CHCO NH C COO-
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Slice through a protein.
Red hydrophilic
Blue hydrophobic
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3. Disulfide bonds
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3. Disulfide bonds
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