Lecture 3 - Protiens Flashcards
Structure of proteins
- non-branching polymers that form macromolecules about 50-100 A in size
- composed of a specific sequence of amino acids joined together by chemical bonds called peptide bonds
- each protein has a distinct unique sequence
- there are 20 different amino acids used to make proteins - they are arranged in a different order and a different length in each different protein.
To understand function, you need to know ___
Structure (3D arrangement of the atoms of a protein)
Different techniques for the routine determination of protein structure
- protein crystallography
- cryo-electron microscopy
- NMR spectroscopy
Almost all completed protein structures are publicly available at locations like the____
Protein data bank
3 different ways of depicting chemical structure
Hydrogens are sometimes omitted from these structures for clarity
‘Ase’ suffix means
Enzyme
Protein responsible for oxygen transport
Hemoglobin
What does hemoglobin do
- binds oxygen in the lungs and carries it in the blood to tissues for use in metabolism
Hormone used in cell signalling
Insulin
What is insulin?
- a peptide hormone secreted after a meal, which b Indy’s to the insulin receptor, signalling cells to take up glucose
Protein involved in metabolism
Hexokinase
Alcohol dehydrogenase
What does hexokinase do?
- hexokinase is an enzyme that adds a phosphate tot glucose, after glucose is taken up by the cell
- kinases are enzymes that usually add phosphate to molecules
Protein involved in digestion
Trypsin
Amylase
What does trypsin do?
- an enzyme that breaks down proteins during digestion
- enzymes that break down proteins are called proteases
____ and ____ make proteins too
Viruses and bacteria make proteins too
HIV PROTESASE (talking)
- HIV gets inside cells and replicate
- it does this by having its genome read and turned into an RNA - then turned into proteins
- HIV makes one long RNA which needs to be chopped up to make lots of smaller RNAs
- HIV protease is made up of two chains with an active site in the middle
- HIV protease binds to poly peptide and breaks the chain at specific points along the polypeptide to make smaller poly peptides that fold up into HIVs proteins - allowing new virus to form
- green structure below shows the inhibitor - allows HIV to be manageable
What is alcohol dehydrogenase
- an enzyme that helps metabolise ethanol
What is ATP synthase
- ATP synthase is a remarkable membrane protein that generates ATP for use in cellular functions
Proteins involved in Immune protection
- antibodies bind to cellular invaders like bacteria and viruses to help protect the body from infection
What does DNA polymerase do?
DNA polymerase binds to one strand of DNA and adds the complementary stand to it
What does RNA polymerase do?
Creases a single strand of RNA that is complementary to one of the strand of duplex DNA
