SCID 141 - LIVING PROCESS: FROM
MOLECULES TO CELL
INSTRUCTOR: KITTISAK YOKTHONGWATTANA, PH.D.
DEPARTMENT OF BIOCHEMISTRY, FACULTY OF SCIENCE, MAHIDOL UNIVERSITY
AMINO ACIDS AND PROTEINS
AMINO ACIDS
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STEREO CHEMISTRY OF AMINO ACIDS
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DIFFERENT SIDE CHAINS OF AMINO ACIDS
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DIFFERENT SIDE CHAINS OF AMINO ACIDS
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DIFFERENT SIDE CHAINS OF AMINO ACIDS
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DIFFERENT SIDE CHAINS OF AMINO ACIDS
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DIFFERENT SIDE CHAINS OF AMINO ACIDS
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AMINO ACID ABBREVIATION
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AMINO ACID ABBREVIATION
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COVALENT BOND FORMATION BETWEEN
AMINO ACIDS – DISULFIDE BOND
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PROTONATION STATES OF AMINO ACIDS
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PROTONATION STATES OF AMINO ACIDS
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PEPTIDE BOND FORMATION
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POLYPEPTIDE CHAIN – PRIMARY STRUCTURE
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POLYPEPTIDE CHAIN FOLDS INTO SECONDARY
STRUCTURE
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 AND  ANGLES
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RAMACHANDRAN PLOT
Image from Voet and Voet, Biochemistry, 4th
Edition, 2011
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WHAT DO AND  ANGLES SIGNIFY?
Image from Voet and Voet, Biochemistry, 4th Edition, 2011
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POLYPEPTIDE CHAIN FOLDS INTO SECONDARY
STRUCTURE – ALPHA HELIX
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MOLECULAR INTERACTION STABILIZING
SECONDARY STRUCTURE IS HYDROGEN BOND
Image from Lippincott, Fig. 2.6
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POLYPEPTIDE CHAIN FOLDS INTO SECONDARY
STRUCTURE – ALPHA HELIX
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POLYPEPTIDE CHAIN FOLDS INTO SECONDARY
STRUCTURE – BETA SHEET
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POLYPEPTIDE CHAIN FOLDS INTO SECONDARY
STRUCTURE – BETA SHEET
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SECONDARY STRUCTURES FOLD INTO
TERTIARY STRUCTURE
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INTERMOLECULAR INTERACTIONS THAT
STABILIZE TERTIARY STRUCTURE
Disulfide bond
formation
Hydrophobic interaction
Images from Lippincott, Fig. 2.9, 2.10
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INTERMOLECULAR INTERACTIONS THAT
STABILIZE TERTIARY STRUCTURE
Ionic interaction
Images from Lippincott, Fig. 2.11
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SOLUBLE PROTEIN
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CHAPERONE-ASSISTED PROTEIN FOLDING –
DnaK/DnaJ SYSTEM
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CHAPERONE-ASSISTED PROTEIN FOLDING –
GroEL/GroES SYSTEM
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TRANSMEMBRANE PROTEIN
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TRANSMEMBRANE PROTEIN
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TRANSMEMBRANE PROTEIN
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TRANSMEMBRANE PROTEIN
Aquaporin
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VOLTAGE-GATED K+ CHANNEL
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EXAMPLE OF CHLORIDE CHANNEL
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QUATERNARY STRUCTURE OF PROTEIN IS THE
ASSEMBLY OF TERTIARY STRUCTURES
http://upload.wikimedia.org/wikipedia/commons/3/3d/1GZX_Haemoglobin.png
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DISULFIDE BOND FORMATION ALSO STABILIZES
PROTEIN QUATERNARY STRUCTURE
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PROTEIN FOLDING SIGNIFIES FUNCTIONS
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COLLAGEN IS A TRIPLE-HELIX PROTEIN
The stability of collagen triple helices
rely on a sharp turn of the helix caused
by an amino acid called hydroxyproline.
Hydroxyproline is produced by
hydroxylation of the amino acid proline
by the enzyme prolyl hydroxylase
following its de novo synthesis (as a
post-translational modification). Such
reaction, which requires vitamin C,
takes place in the lumen of the
endoplasmic reticulum.
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http://en.wikipedia.org/wiki/Hydroxyproline#mediaviewer/File:Hydroxyproline_structure.svg
ACTIN – MYOSIN ARE MAJOR PROTEINS IN
MYOCYTES
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ACTIN – MYOSIN ARE MAJOR PROTEINS IN
MYOCYTES
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ACTIN – MYOSIN ARE MAJOR PROTEINS IN
MYOCYTES
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MYOSIN MOTOR
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ACTIN
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MOVEMENT OF MYOSIN MOTOR ON ACTIN
FILAMENT
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IMMUNOGLOBULIN PROTEINS - IgG
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IMMUNOGLOBULIN PROTEINS
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IMMUNOGLOBULIN PROTEINS - IgM
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PHAGOCYTOSIS OF AN ANTIBODYBOUND VIRUS BY A MACROPHAGE
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HEMOGLOBIN
Hemoglobin
Myoglobin
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HEME STRUCTURE WITHIN HEMOGLOBIN
UPON OXYGEN BINDING
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THE BOHR EFFECT
CO2 and H+ ions also are effectors of
hemoglobin. In active muscle cells, oxygen is
rapidly consumed and carbon dioxide and H+
ions are produced.
O2 affinity decreases at lower pH. As
hemoglobin moves into a tissue with lower pH,
it can more easily unload oxygen.
Increase in CO2 concentrations have the same
effect.
In combination, the effect of pH and CO2 allow
nearly 90% of the oxygen bound in the lungs to
be unloaded in tissues where it is required.
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STRUCTURAL BASIS OF THE BOHR EFFECT
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BPG BINDING STABILIZES THE T STATE
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SICKLE CELL ANEMIA
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