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DID YOU MISS THE TEST BEFORE THE BREAK? Today is the last day to make it up in tutorial. Open to yesterday’s entry- Entry 11. Proteins: Amino Acids in 3 D- 2/27/12 Let’s review what we talked about yesterday. 2 Types of Proteins. - PowerPoint PPT Presentation
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DID YOU MISS THE TEST BEFORE THE BREAK? Today is the last day to make it up in tutorial.
Open to yesterday’s entry- Entry 11. Proteins: Amino Acids in 3 D- 2/27/12Let’s review what we talked about yesterday.
2 Types of Proteins1) Structural – proteins that form physical parts.
Examples – -keratin (hair and nails)-actin (muscle)-microtubules (cell membrane
skeletons) - gelatin
- collagen
2) Functional – Proteins that have activityExamples--Hormones – used for signaling-Defensive – antibodies that recognize foreign
invaders-Transport – Carrier proteins!!!-Enzymes – used for chemical reaction- Hemoglobin – found on RBC and carry oxygen
Protein Shape Determines Function
Example – Fibrous proteins are long and thin, and are used for structure
What will we learn today?
HOW is the shape of a protein determined.
Proteins are made ofchains of amino acids
What are amino acids?
Link to amino acid 3-D models
H2NAminogroup C
Side chain
R
H
C
O
OH
Carboxylgroup
Non-ionized form
There are 20 different amino acids. All have the same general form.
CCO
O–
H
H3N+
H
Glycine (G)Gly
C CO
O–
H
H3N+
CH3
Alanine (A)Ala
C CO
O–
H
H3N+
CHH3C CH3
Valine (V)Val
C CO
O–
H
H3N+
CH2
H3C CH3
Leucine (L)Leu
CH
CCO
O–
H
H3N+
CH
Isoleucine (I)Ile
CH3
CH2
H3C
Side chains contain carbon and/or hydrogen
CO
O–C
CH2
CH2
H2C
H2N+
H
Proline (P)Pro
Each amino acid has a different side chain.
CH3N+
CH2
H
C
O
O–
Phenylalanine (F)Phe
CH3N+
CH2
H
C
O
O–
Tyrosine (Y)Tyr
OH
CH3N+
CH2
H
C
O
O–
NH
Tryptophan (W)Trp
Side chains contain ring structures
Each amino acid has a different side chain.
CH3
CH2
CH2
S
C CH3N+
HO
O–
Methionine (M)Met
SH
CH2
C CH3N+
HO
O–
Cysteine (C)Cys
Side chains contain sulfur
Each amino acid has a different side chain.
OH
CH2
C CH3N+
HO
O–
Serine (S)Ser
Threonine (T)Thr
CH
C CH3N+
HO
O–
CH3HO
Side chains contain hydroxyl functional groups
Each amino acid has a different side chain.
C
CH2
C CH3N+
HO
O–
H2N O
Asparagine (N)Asn
CH2
C CH3N+
HO
O–
CH2
C
OH2N
Glutamine (Q)Gln
Side chains contain amino functional groups
Each amino acid has a different side chain.
CH2
C CH3N+
HO
O–
NH
+NH
Histidine (H)His
CH2
C CH3N+
HO
O–
CH2
CH2
+NH3
CH2
Lysine (K)Lys
Basic side chains
CH2
C CH3N+
HO
O–
CH2
CH2
NH
C +NH2
NH2
Arginine (R)Arg
Each amino acid has a different side chain.
CH2
C CH3N+
HO
O–
C
O– O
Aspartate (D)Asp
Acidic side chains
CH2
C CH3N+
HO
O–
CH2
C
O– O
Glutamate (E)Glu
Each amino acid has a different side chain.
H
H H H H H HO O O H H O H H O
N C C N NC C C C
H CH3 CH2
OH
N-terminus
N C C
CH2
C
O
OH
CH2
N C C
CH
CH3H3C
CH2
OH
H H O
N C C
H H O
N C C
H H O
N C C
CH2
SH
OH
C-terminus
H2N
H
H
C CO
OHCarboxylgroup
H2N
H
CH3
C CO
OHAminogroup
H2N
H
H
C
O
C N CC
HH
CH3
OH
O
Peptidebond
+ H2O
H2N Gly Ala Ser Asp
N-terminus
21 3 54 6 7 8
Phe Val Tyr Cys
C-terminus
COOH
+
Proteins are chains of amino acids
Protein Model activityPeptides are chains of amino acids and
sometimes used as another word for protein. Get four amino acids per table (group of two)
Follow the instructions of your teacher to build peptides using the paper amino acid models for questions #1-4.
Then join your chain with another groups chain to form an 8 amino acid chain for #5
Amino Acid sequence determines the 3-D protein shape
• Interactions between amino acids cause folding and bending of the chainExamples: – positive (+) and negative (-) parts of amino
acids are attracted to each other.– hydrophobic regions are attracted to each
other– Sulfur is attracted to each otherMUST be an amino acid between them to attach by paper clips
COMPLETE #6-7
CH2 OH CH2C
O
N
H
HHydrogen bond between
two side chains
CH2 OH O C
OC H N
CH2CH
CH3
CH3
Hydrogen bond betweenside chain and peptide group
Hydrogen bond between peptide
groupsH3C
H3C
CHCH2
Hydrophobicinteraction
CH2 CH2S S
Disulfide bond
Ionic bond
(CH2)4 NH3+ –O
O
CCCH2
Figure 3.11a
Interactions that determine the structure of proteins
#8:
CYS- LEU- ARG- GLY- GLY-GLY- ASP- LEU- CYSS S
+ -
hydrophobic
hydrophobic
9. HOW WOULD YOU BE ABLE TO BUILD A COMPLETELY DIFFERENT PROTEIN USING THE SAME 8 AMINO ACIDS?• You could change the order (sequence of the
amino acids) which makes it a different shape (different protein).
• From yesterday: The shape of a protein determines its function.
• Now we know….The shape is determined by the sequence/order of amino acids and their interactions with each other.
Make an entry- Entry 12: Lactose Intolerance- 2/28/12See attached entryRead the information and answer questions on the worksheet.It will be homework if you don’t finish it.
