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PROTEIN - Coggle Diagram
PROTEIN
What is protein??
made from small building block called "Amino acid"
Types of amino acids
proteinogenic
found in polypeptide chain after translation
non-proteinogenic
chemically modified
cannot be found in protein chains
Function of amino acids
precussors of a variety of complex nitrogen containing molecules
as chemical messenger
as metabolic intermediate
building block of proteins
Characteristics of amino acids
zwitterionic
have two charge
effect
high melting point
soluble in aqueous solvent , not in non-aqueous solvent
good biological buffer
can form isomers
naturally occuring in L-isomers
enantiomer & optically active- D & L-
alpha carbon (chiral) exception: Gly
Classification
Aliphatic amino acids
glycine
alanine
valine
leucine
isoleucine
Aromatic amino acids
phenylalanine
tyrosine
tryptophan
Cyclic amino acids
proline
Hydroxyl and sulfur containing amino acids
serine
threonine
cysteine
methionine
Basic amino acids
lysine
arginine
histidine
Acidic amino acids and their amides
aspartate
the amide is
asparagine
glutamate
the amide is
glutamine
Example:
alpha keratin (hair and nail)
actin and myosin (muscle movement)
hemoglobin (carry oxygen in blood)
receptor protein (transmit signal inside cell)
General Structure
Hierarchy
classified into
Secondary structure
stabilize by hydrogen bond
two types
alpha helix
right handed helix
contain 12 residue
hydrogen bond via: one amino acid with the forth amino acid
R-group projected outwards
rigid, rod like-shape
beta pleated sheet
sheet arranged side by side (zig-zag)
parallel type
antiparallel type
Tertiary structure
Primary structure
read from N-terminus to C-terminus
Quatenary structure
