Biochemistry and Structural Biology

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Biochemistry and Structural Biology
BCB 444/544 Introduction to BioinformaticsLect
ure 6

• 6_Sep01

Some slides adapted from a presentation by Erin
Garland
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DNA Structure

• 4 bases A, C, T, G
• Sugar-phosphate backbone strings the bases
  together (and gives DNA a negative charge)
• DNA is double stranded
• Strands are held together by base pairs
• DNA forms a double helix

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DNA structure

• Only 4 nucleotides (bases) make up all DNA
• A (adenine)
• C (cytosine)
• T (thymine)
• G (guanine)

- T - G - A - C
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Base Pairing Rules

• A always pairs with T
• C always pairs with G
• These pairs are often called Watson-Crick base
  pairs
• These rules are vital for
• DNA replication
• Transcription of RNA

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(No Transcript)
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Chromosome packing
DNA containing genes is tightly packed into
chromosomes
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RNA vs. DNA
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RNA Structure

• RNA also has 4 bases A, C, G, and U (instead of
  T)
• RNA is made as a single strand and then forms a
  variety of single and double stranded structures
  by folding up and base pairing to itself

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RNA Structure Pics
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tRNA Structure
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Protein Structure

• Proteins are composed of amino acids
• There are 20 amino acids in proteins
• Each amino acid has a different structure and
  different properties

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Web resources

• Books website

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Levels of protein structure

• We commonly talk about four levels of protein
  structure
• Primary (1) structure is the amino acid sequence
• Secondary (2) structure is local structure such
  as a-helix or ß-sheet
• Tertiary (3) structure is the fully folded
  three dimensional structure of a protein
• Quaternary (4 ) structure is multiple subunits
  put together

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Protein structure pics
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Sequence-Structure-Function

• Amino acid sequence determines protein structure
• Protein structure determines function

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Dystrophin Example
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Circuit Diagram View
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Metabolic pathways
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Close-up view of Glycolysis
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Signal transduction pathways
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Enzymes and catalysis
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Antibodies

• Used by the immune system to recognize foreign
  objects
• Tags the foreign object for destruction

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Immunofluorescence Immunoprecipitation

• Books website