amino acids and proteins 1.what is an amino acid / protein 2.where are they found 3.properties of...
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Amino Acids and Proteins
1.What is an amino acid / protein
2.Where are they found
3.Properties of the amino acids
4.How are proteins synthesized1.Transcription & translation
Amino Acids
Amine and carboxyl groups. Sidechain ‘R’ is attached to C-alpha carbon
The amino acids found in Living organisms are L-amino acids
Transcription & translation
DNA | TranscriptionmRNA
| TranslationProtein
In higher organisms thepicture is a bit more complex.DNA -> pre-mRNA -> mRNA->protein
Protein might need a chaperonein order to fold correctly.
movie
Proteins - where are they found
1. Proteins are found in all living organisms2. In humans there are approx 25.000 proteins3. Each protein has a specific function
1. Making up the human tissue - skin, hair, heart ...2. Degrading the food we eat3. Immune system4. Transportation of Oxygen in blood5. Triggering the growth of cells6. The brain - neural signalling
4. Typically a protein is approx 220 aa in human5. Proteins talk, i.e. Protein-protein interactions
1. To relay a signal across the cell-membrane
1 and 3-letter codes
1.There are 20 naturally occurring amino acids2.Normally the one/three codes are used
Ala - ACys - CAsp - DGlu - EPhe - FGly - GHis - HIle - ILys - KLeu - L
Met - MAsn - NPro - PGln - QArg - RSer - SThr - TVal - VTrp - WTyr - Y
Graphic stick representationDifferent aa, different
property
Ile - Hydrophobic
Phe - Hydrophobic & aromatic
Charged amino acids(sidechain in red)
QuickTime™ and a decompressor
are needed to see this picture.Arg - R
Lys - K
Asp - D
Glu - E
His - H
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Neutral amino acids
Ile - I
Leu - L
Met - M
Phe - F
Pro - P
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Property of amino acids (I)neutral, polar or charged ?
Ala - A
Asn - N
Cys - C
Gln - Q
Gly - G
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Property of amino acids (II)neutral, polar or charged ?
Ser - S
Thr - T
Trp - W
Tyr - Y
Val - V
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QuickTime™ and a decompressor
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QuickTime™ and a decompressor
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Protein structure
Primary structure: Amino acids sequences
Secondary structure: Helix/Beta sheet
Tertiary structure: Fold, 3D cordinates
Protein structure-helix
helix 3 residues/turn - few, but not uncommon-helix 3.6 residues/turn - by far the most common helixPi-helix 4.1 residues/turn - very rare
Protein folds
Class4’th is ‘few secondary structure
ArchitectureOverall shape of a domain
TopologyShare secondary structure connectivity
Summary
DNA -> mRNA -> Protein
transcription translation
1.20 naturally occurring amino acids
2.Each amino acid has different properties, but can be grouped into:1.Charged, neutral, polar (basic, acidic)
3.Secondary structure. -helix & -strand/-sheet
4.Protein hydrophobic inside, polar on the outside
5.Folds or classes: all , all , +, few secondar structure elements