•MOLECULAR CELL BIOLOGY • SIXTH EDITION • CHAPTER 3 • Protein Structure and Function

Lodish • Berk • Kaiser • Krieger • Scott • Bretscher •Ploegh • Matsudaira
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• MOLECULARCELL x




BIOLOGY x




• SIXTH EDITION x




• CHAPTER 3 x




• 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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Ribbon diagram
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,Conformations Functional classes: x




x Structural proteins
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x Structural proteins
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x Scaffold protein
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x Transport proteins
x




x Transport protein
x


x Regulatoryproteins x




x Regulatoryprotein x



x Motor proteins
x




x enzymes



Different conformation = different function
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, Hierarchical structure of proteins x x x




Proteins are single, unbranched chains of amino acid monomers
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There are 20 different amino acids; All amino acids have the same general
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structure 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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In turn, a protein’s structure determines the function of that protein
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pK2 H pK1
+ -
H3N C COO

R