Topics for Today  Natural Curls?

Topics for Today  How do proteins get their shape?

Chapter 12  12.3 Cracking the chemical code (p. 539 on proteins only)

Chapter 5  5.6 The role of hydrogen bonding  5.6 The role of hydrogen bonding

Topics for Friday  Closing Remarks  Quiz #11 (Don’t be late!)

Topics for Friday  If you are > 5 minutes late… No quiz for you!

Announcements! HW 5 due tomorrow Psst… easy 10 points!

Announcements! Final Exam Friday, May 18 at 12:25 pm in 113 Psychology! NOT here!

Announcements! Final Exam Don’t forget about the essay!

Ever wondered how we measure metals in atmospheric PM? NO! Still, you’re all invited to a special talk on Friday!!!

Dr. Majestic Talks About His Research! 12:05 pm THIS Friday; 102 Water Science and Engr Lab!!

Topics for Today  How do proteins get their shape?

Review What is a protein??

A polymer of amino acids!! …amide-ala-amide-gly-amide-leu-amide- ile-amide-glu-amide-arg-amide-asp-amide- ala…

Keratin, … Keratin, … A protein that contains a high content of cysteine. A protein that contains a high content of cysteine.

Glycine (gly) Alanine (Ala) Valine (Val) Leucine (Leu) Isoleucine (Ile) Proline (Pro) Tryptophan (Trp) Phenylalanine (Phe) Serine (Ser) Threonine (Thr) Tyrosine (Tyr) Aspartic acid (Asp) Glutamic acid (Glu) Asparagine (Asn) Glutamine (Gln) Lysine (Lys) Arginine (Arg) Histidine(His) Cysteine (Cys) Methionine (Met)

 Cysteine R = –CH 2 –S–H R = –CH 2 –S–H  Methionine R = –CH 2 –CH 2 –S–CH 3 R = –CH 2 –CH 2 –S–CH 3 Contains sulfur!!

Keratin, … Keratin, … Where is keratin found? Hair!

Hair  ~90% protein (keratin)

Hair  Also contains melanin Skin pigment

Keratin  The chains of amino acids form a coil Why a coil?

The side chains give the protein its shape!

Keratin  Nonpolar R groups on the outside of the coil R R R R R Water repelling (hydrophobic)

Charged groups on the outside.

Keratin R R R R R What about the R groups inside?

Keratin R R R R R These help give hair its structure

R groups that … (1) contain –SH and form disulfide bonds (2) are ionic and attract each other (3) hydrogen bond to each other What gives hair its structure?

R groups that … (1) contain –SH and form disulfide bonds (2) are ionic and attract each other (3) hydrogen bond to each other Permanents change these hair curlers disrupt these What gives hair its structure?

R groups that … (1) contain –SH and form disulfide bonds (2) are ionic and attract each other (3) hydrogen bond to each other What gives hair its structure?

 1) It’s bent  2) It’s polar  3) Polar things dissolved in water  4) Formed from acid-base reactions  5) Formed from making Nylon and PET  6) Anywhere from ½ to ¾ of our body  7) Forms ions in small amounts O H H.. What do we know about water? Review

What else do we know about water?

Fig Hydrogen bonds! What are H-bonds?

Fig δ-δ- δ+δ+ δ+δ+ δ-δ- δ+δ+ δ+δ+ δ-δ- δ+δ+ δ+δ+ δ-δ- δ+δ+ δ+δ+ δ-δ- δ+δ+ δ+δ+

Hydrogen bonds  Not really bonds, at all! Just a strong attraction! Need a dipole!!

Can non-water molecules H- bond?

Fig N H.. δ-δ- δ+δ+ δ+δ+ δ-δ- δ+δ+ δ+δ+ δ-δ- δ+δ+ δ+δ+ δ-δ- δ+δ+ δ+δ+ δ-δ- δ+δ+ δ+δ+ δ+δ+ Hydrogen bonds?

Fig Hydrogen bonds… N H.. δ-δ- δ+δ+ δ+δ+ δ-δ- δ+δ+ δ+δ+ δ-δ- δ+δ+ δ+δ+ δ-δ- δ+δ+ δ+δ+ δ-δ- δ+δ+ δ+δ+ δ+δ+

H bonds  Occur when H is attached to an electronegative atom such as O, N or F. page 231

Amino Acids Glycine (gly) Alanine (Ala) Valine (Val) Leucine (Leu) Isoleucine (Ile) Proline (Pro) Tryptophan (Trp) Phenylalanine (Phe) Serine (Ser) Threonine (Thr) Tyrosine (Tyr) Aspartic acid (Asp) Glutamic acid (Glu) Asparagine (Asn) Glutamine (Gln) Lysine (Lys) Arginine (Arg) Histidine(His) Cysteine (Cys) Methionine (Met) Which amino acids will H- bond?

Hydrogen bonds NH – O– O

R groups that … (1) contain –SH and form disulfide bonds (2) are ionic and attract each other (3) hydrogen bond to each other What gives hair its structure?

H O H O | // | // H 2 N — C — C H 2 N — C — C | \ | \ CH 2 OH CH 2 OH | SH SH Cysteine

R = CH 2 – SH – SH HS – Amide Backbone

Disulfide bonds – S – S – Not easily broken!!

Disulfide bonds – S – S – A “permanent”

– SH HS – Reset the strands Break the disulfide bonds!

– S – S –

Summary A permanent –Break the S – S bonds –Wrap hair around a curler –Reform S – S bonds to permanently change the shape

R groups that … (1) contain –SH and form disulfide bonds (2) are ionic and attract each other (3) hydrogen bond to each other What gives hair its structure?

(3) Acidic  R group contains carboxylic acid REVIEW

Aspartic acid REVIEW

Aspartic acid NEW COOH can ionize to COO — and H +

(4) Basic  R contains an amine group REVIEW

Lysine

Lysine NEW NH 2 can gain H + to become NH 3 +

Ionic bond  The acidic groups, –COOH, can lose a H + and become –COO –  The basic groups, –NH 2, can gain a H + and become –NH and – attract!

Proteins Polymers of amino acids But how are they made?

Protein synthesis video!!

Hippies reenact protein synthesis - A Protein Primer

The Jabberwocky

Twas brillig, and the slithy toves Did gyre and gimble in the wabe: All mimsy were the borogoves, And the mome raths outgrabe. "Beware the Jabberwock, my son! The jaws that bite, the claws that catch! Beware the Jubjub bird, and shun The frumious Bandersnatch!" He took his vorpal sword in hand: Long time the manxome foe he sought -- So rested he by the Tumtum tree, And stood awhile in thought. And, as in uffish thought he stood, The Jabberwock, with eyes of flame, Came whiffling through the tulgey wood, And burbled as it came! One, two! One, two! And through and through The vorpal blade went snicker- snack! He left it dead, and with its head He went galumphing back. "And, has thou slain the Jabberwock? Come to my arms, my beamish boy! O frabjous day! Callooh! Callay!' He chortled in his joy. `Twas brillig, and the slithy toves Did gyre and gimble in the wabe; All mimsy were the borogoves, And the mome raths outgrabe.