L6 Lysozymes Flashcards
What do the curved arrows show?
They show the direction of electron movement
What’s a nucleophile and an electrophile ?
Nucleophile supplies electrons
Electrophile accepts electrons
Which is stronger, a sigma bond or a pie bond?
Sigma bond is stronger than
What is an Sn2 reaction?
Substitution nucleophilic bimolecular.
When a nucleophile (lone pair) attacks an electrophilic carbon atom, simultaneously displacing a leaving group
For example: bromine ion kicking out the iodine due to difference in electronegativity
What is a lysozyme?
Lysozyme is an enzyme that is involved in the first line of defense against bacterial attack that cleaves peptidoglycan
Where is lysozymes mostly found in?
Bodily secretions including tears and nasal mucus
Which group do lysozymes belong to?
Glycosidase enzymes
The lysozyme structure is separated into two lobes (domains). What makes both domains and what separates it?
One domain - small beta sheet of mainly hydrophilic residues
One domain - a hydrophobic core surrounded by short alpha helices
A deep cleft separates it
How many sugars can the active site cleft of lysozymes bind to?
Six sugar molecules at once
In between which sugars is the glycosidic bond broken?
The glycosidic bond is broken between the 4th and 5th sugars (D-E)
Which two sugar molecules that are essential compounds of the bacterial cell wall are broke down by lysozyme?
Lysozyme cuts a glycosidic bond between NAM and NAG sugars in bacterial peptidoglycan
What are Glu35 and Asp52?
They are specific amino acid residues within the lysozyme protein. Located in the active site of lysozyme
What is so special with Asp 52 in initiating the breakage of the glycosidic bond?
Asp52 is in the carboxylate form as expected at pH 6.
Causes a nucleophilic attack (donated electron)
