Proteins

1. Proteins • Most abundant type of molecules in cells • Several hundred thousand in our bodies! • Responsible for most biological functions

2. Proteins are worker molecules that are necessary for virtually every activity in your body

3. Proteins during Development

4. Unique Structures = Unique Functions • Collagen in our cartilage and tendons gains its strength from its three-stranded, rope-like structure. • Found outside and inside the cell. • Antibodies are immune system proteins that rid the body of foreign material, including bacteria and viruses. • The two arms of the Y-shaped antibody bind to a foreign molecule. • The stem of the antibody sends signals to recruit other members of the immune system. • Found in blood and other body fluids

5. Unique Structures = Unique Functions • Some proteins latch onto and regulate the activity of our genetic material, DNA. • Some of these proteins are donut shaped, enabling them to form a complete ring around the DNA. DNA polymerase III • Enzymes - proteins that facilitate chemical reactions • often contain a groove or pocket to hold the molecule they act upon. Shown here (clockwise from top) are luciferase, amylase, and reverse transcriptase

6. GFP

7. Protein Basics • Proteins are polymers assembled from amino acids • 20 different amino acids are used • Bond between amino acids is called the "Peptide Bond". • Peptide Bond is formed between the carboxyl group of one amino acid and the alpha amino group of another amino acid.

8. The green fluorescent protein (GFP) is composed of 238 amino acids, originally isolated from the jellyfish Aequorea victoria that fluoresces green when exposed to blue light. You have become a mad scientist with a mission to make a human being glow. You and your colleagues have in your hands the protein sequence of green fluorescent protein (GFP). What steps do you take to make this twisted dream come true? Amino Acid Sequence of GFP: MetSerLysGlyAlaLeuIleValProSerTyrPheProThrThrSTOP

10. RNA • Single stranded • Ribose • U instead of T • Same base pair rules apply • Generally unstable and degrades easily • If have the amino acid sequence, can figure out the sequence of the mRNA

11. Amino Acid Sequence of GFP: MetSerLysGlyAlaLeuIleValProSerTyrPheProThrThrSTOP How do you get the mRNA sequence? AUG AGU AAG GGA Now you finish it!

12. AUG AGU/C AAA/G GGU/C/A/G GCU/C/A/G CUU/C/A/G AUU/C/A GUU/C/A/G CCU/C/A/G UCU/C/A/G UAU/C UUU/C CCU/C/A/G ACU/C/A/G ACU/C/A/G What can be done with this to make your baby glow?

13. DNA • Double stranded • Deoxyribose • T instead of U • Same base pair rules apply • Passed from one cell to the next • If have the mRNA sequence, can figure out the gene sequence!

14. Let’s make a gene! mRNA sequence: DNA sequence: AUG AGC AAG GGA GCC CUG AUU GUA CCG UCG UAC UUU CCA ACU ACC TAC TCG TTC CCT CGG GAC TAA CAT GGC AGC ATG AAA GGT TGA TGG ATG AGC AAG GGA GCC CTG ATT GTA CCG TCG TAC TTT CCA ACT ACC

15. Since GFP protein can be produced in EVERY cell via the gene, we now have a glowing baby!!!!

16. How is the GFP gene passed on to the next cell? • DNA replication occurs before mitosis • Occurs when chromosomes duplicate (make copies) • An exact copy of the DNA is produced with the aid of the enzyme DNA polymerase • Hydrogen bonds between bases break and enzymes “unzip” the molecule • Each old strand of nucleotides serves as a template for each new strand • New nucleotides move into complementary positions are joined by DNA polymerase

17. Two New, Identical DNA Strands Result from Replication Video

18. Replication DNA Transcription RNA Nucleus Translation Protein . Cytoplasm Central Dogma: How it happens in the cell! Animation! Animation!

19. Human Genome • 3.2 million DNA base pairs • 1.5% encode proteins < = > 98.5% not protein encoding • ~ 31,000 genes encoding 100,000 - 200,000 proteins • How are 100,000 to 200,000 proteins produced from 31,000 genes? • What is the 98.5% of the human genome that does not encode proteins?

20. RNA Processing Video

21. Translation In the Cell