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Introduction to Studying Proteins. What is going on?. ?. Study Questions. Describe the structure of proteins, including the significance of amino acid R-groups and their impact on the three-dimensional structure of proteins.
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Introduction to Studying Proteins
Study Questions • Describe the structure of proteins, including the significance of amino acid R-groups and their impact on the three-dimensional structure of proteins. • Explain the steps of transcription and translation in protein synthesis. • Discuss the role of naturally occurring proteins and recombinant proteins in biotechnology. • Differentiate proteins that function as part of structure, as antibodies, and as enzymes. • Describe the structure of antibodies and explain the relationship between antibodies and antigens. • Discriminate among the classes of enzymes and discuss the effect of reaction conditions on enzyme activity. • Summarize polyacrylamide gel electrophoresis and identify its usefulness for studying proteins.
5.1 The Structure and Function of Proteins • Virtually all biotechnology products have something to do with proteins. • Protein has a three-dimensional structure.
Protein Molecule Structure • Polymers composed of amino acids • Twenty different kinds of amino acids are found in protein • Most proteins contain tens of hundreds of amino acids Function of Structural Proteins For an HIV particle to recognize, attach, and infect a T-helper cell, the gp210 structure must be a precise shape and must exactly match its human cell membrane receptors Function of Antibody Proteins Recognize and bind foreign proteins or other molecules (antigens) for removal from the body
Protein Structure is Complex • Primary structure – the order and type of amino acids found in a polypeptide chain • Secondary structure – the structure of a protein (alpha helix and beta sheets) that results from hydrogen bonding • Tertiary structure – the structure of a protein that results from several interactions, the presence of charged or uncharged “R” groups, and hydrogen bonding • Quaternary structure – the structure of a protein resulting from the association of two or more polypeptide chains
Studying Proteins What and how?
5.2 The Production of Protein Until recently, proteins could only be made in cells. Now small polypeptide chains can be synthesized in the laboratory. Overview of Protein Synthesis Protein synthesis occurs continuously throughout a cell’s life Eukaryote and prokaryote – protein synthesis is similar
Protein Synthesis in a Eukaryotic Cell. In a eukaryotic cell, DNA is located within chromosomes in the nucleus. The mRNA transcripts carry the DNA code out to the ribosomes, which translate the code into a strand of amino acids.
Transcription and Translation Protein synthesis is a two-step process: First Step: Genetic code must be rewritten onto a messenger molecule
Second Step: mRNA nucleotide code is rendered into a sequence of amino acids
The Importance of Proteins in Biotech R&D The ability to synthesize and modify peptides or proteins is crucial to the production of virtually every biotechnology product.
Enzymes: Protein Catalysts Enzymes are proteins that act as catalysts Enzymes are involved in virtually every reaction in a cell Many companies have focused on producing enzymes for sale Enzymes and Their Substrates The molecules upon which enzymes act are called substrates
Applications of Protein Analysis Protein profile of cells and tissues A protein’s structure can help explain its function Chemical processes in cells Evolution and taxonomic relationships
Advanced Protein Studies A single gene can encode for as many as 50 different protein forms. X-Ray Crystallography Protein (x-ray) crystallography visualizes the positions of atoms in a molecule based on x-ray wave diffraction, and the constructive and destructive interference that results off the atoms in the sample.
ELISA ELISA is one of the most frequently used assays in protein manufacturing. Western Blots Running samples on acrylamide gels can provide a great deal of information about the proteins in a sample.
Other Advances and Applications of Biotechnology • Pharmacogenetics • Environmental biotechnology • Biodefense Pharmacogenetics – Personalized Medicines Since every person’s DNA is different, doctors will be able to design and modify drugs to better meet individual needs.
Environmental Biotech This is a vast field with many applications for monitoring and correcting the health of entire species, populations, communities, and ecosystems. Biodefense: Protection Against Bioterrorism Biodefense is the term for all of the methods used to protect people from exposure to biological agents.