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• MOLECULARCELL fk
BIOLOGY fk
• SIXTH EDITION fk
• CHAPTER 3 fk
• Protein Structure and Function
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© 2008 W. H. Freeman and Company
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, Human
signaling
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proteinkeapl
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Ribbondiagram
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,Conformations Functional classes: fk
fk Structural proteins fk
fk Structural proteins fk
fk Scaffold protein
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fk Transport proteins
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fk Transport protein fk
fk Regulatoryproteins fk
Regulatoryprotein
Motor proteins
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fk enzymes
Different conformation = different function
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, Hierarchicalstructureofproteins kf kf kf
Proteinsaresingle,unbranchedchains ofaminoacidmonomers
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There are 20 different amino acids; All amino acids have the same general structure
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but the side chain (R group) of each is different
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A protein’s amino acid sequence determines its three-dimensional structure
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(conformation)
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Inturn,aprotein’sstructuredeterminesthefunctionofthatprotein
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pK2 H pK1
+ -
H3N C COO
R