Download Proteins

Proteins
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Aminoacids are called as Magic 20 because they form the basic components of life
Amino acids are Mono or Di carboxylic acids with one or two amino groups (NH2).
Essential amino acids cannot be synthesized in the body
Essential amino acids are 1 to 8 in adults and 1 to 10 in children
The 10 essential amino acids are, Valine, Leucine, Isoleucine, Phenylalanine,
Tryptophan,Methionine,Lysine,Threonine,Arginine and Histidine.
Easy way to remember 7 essential amino acids is the code HIT LAMP – Histidine, Isoleucine, Tryptophan, Lysine,
Arginine, Methione, Phenylalanine
Non essential amino acids can be synthesized in the body
The 10 non essential amino acids are Alanine, Serine, Proline, Glutamic acid, Aspartic acid, Tyrosine, Cysteine,
Asparagine, Glutamine and Glycine.
Easy way to remember non essential amino acids is the codes ACT – Alanine-Cysteine-Tyrosine, GAP – Glutamic
acid-Aspartic acid- Proline, GAS – Glycine-Asparagine-Serine
Non protein forms of amino acids are Ornithine, Citrulline, Cystine and Methionine.
Easy way to remember Non protein amino acids is the code MOC – Methionine-Ornithine-Citrulline
Sulphur containing amino acids – Methionine, Cysteine, Cystine
Simplest amino acid- Glycine. No assymetryic carbon atom present
Derived amino acid – Cystine. Formed from other amino acids by enzymatic reaction
Alkaline amino acids having Alkyl side chains- Glycine, Alanine, Valine, Leucine, Isoleucine
Aromatic amino acid – Phenyl alanine, Tyrosine, Tryptophan
Basic amino acid – R group contains nitrogen atom- Lysine, Arginine
Dibasic amino acids- Lysine, Arginine, Histidine
Acidic amino acids- R group contains carboxyl acid
Isoelectric pH- pH at which amino acid becomes neutral in Zwitter ion form. Symbol is pI.
Polypeptide is the Primary structure of protein
Secondary structure- local 3D folding of polypeptides by covalent bonds- Alpha helix, Beta pleated sheet
Tertiary structure- Further folding of secondary structure- Myoglobin
Native conformation- Natural conformation by unique arrangement of amino acids
Structural Motifs- Peculiar combination of secondary structure of proteins
Chaperones- Heat shock proteins. Synthesized when the temperature rises
Salt linkage-Electrostatic or Ionic linkages found in Proteins
Protein data book- Structure of various Proteins is studied using X ray diffraction and stored in data base
Methods to separate proteins- Electrophoresis, Chromatography, HPLC, Affinity chromatography
London dispersion and Vander Waal forces- Weakest of non covalent bonds
Beta pleated structure- Beta helix structure of proteins
Alpha helix- Formed by hydrogen bonding between C=O and N-H groups of peptide bonds
Forces of proteins- Hydrogen bond, Ionic bond, Covalent bond, Hydrophobic bond
NMR- Nuclear Magnetic Resonance. Used to study protein structure
M-Protein- Antiphagocytic protein present on the cell surface of Streptococci. Prevents Complement deposition
G-Proteins- Transmembrane signaling surface receptor proteins. Hormones, neurotransmitters etc pass through
cell membrane with the help of G proteins
Ramachandran Plot- In 1940, Linus Pauling and Robert Corey determined the X ray structure of amino acids to
study the conformation of proteins.Based on this, in 1954, Ramachandran and Kartha proposed “Triple helical
coiled-coin” structure of Collagen. The protein structure is formed of helix and the formation of helix is due to
Steric repulsion between groups of atoms in the polypeptide chains
38. Zinc Finger proteins- Component of Prokaryotic gene regulator. Discovered by Auron Klug in the transcription
factor III of Xenopus. It contains Zinc