Protein Structure: X-ray Crystallography Objectives ?To review the basics of protein structure (primary, secondary, tertiary and quaternary)
?Understand the basic principles and steps in
protein crystallization and protein crystallography
?For example
Why protein structure ? ?In the factory of living cells, proteins are the
workers, performing a variety of biological tasks.
Structure implies function ?Each protein has a particular 3-D structure that
determines its function.
?Structure is more conserved than sequence.
Structure ? Origins/Evolution
Protein Structures
Primary
Secondary
Tertiary
Quaternary
Amino acid sequence.
Alpha helices & Beta sheets, Loops.
Arrangement of secondary elements in 3D space.
Packing of several polypeptide chains.
Given an amino acid sequence, we are interested in its secondary structures, and how they are arranged in higher structures.
Protein Structures
(1) Primary structure ?
Details of amino sequence of a protein is the primary sequence. ?Number of amino acids ?Their order
Primary structure will determine all other levels of structural organization of a protein.
First study of a protein will be its sequence determination. The dermination of the primary structure:
?N-terminal: Sanger's method, Edman's method ?C-terminal: Carboxypeptidase
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X-射线衍射法解析蛋白质结构1
