Exam 1 Quiz 2 Flashcards
(31 cards)
Group translocations
proteins work together to chemically modify an incoming molecule causing the sugar to always travel down the concentration gradient
Sugar phosphotransferase system
phosphoenol pyruvate (PEP), more phosphate across a group of enzymes
In PEP, is a mutation in enzyme 1 or enzyme 2 worse?
mutation in enzyme 1 is worse than a mutation in enzyme 2
Enzyme 1
constant across all sugars
Enzyme 2
changes depending on the sugar that is being brought in
Siderophores
important for getting iron into the cell in both prokaryotes and eukaryotes
Why is uptake of iron made difficult?
extreme insolubility of iron
common (specific) names for siderophores
-Ferrichrome
-Enterobactin
What do siderophores steal from human systems?
take iron from our systems and attach to siderophores
Sec-dependent pathway
-bacterial system
-ATP mediated
-transports unfolded proteins
-requires signal peptides within secreted proteins
signal peptides (sec-dependent)
-15-20 amino acids long
-sequence is variable but follows certain characters
signal peptide characters
-found in N terminus
-few positively charged amino acids
-hydrophobic core
-polar grouping of amino acids closer to C terminus
Recognition for sec-dependent pathway
Sec A and SRP
Sec A
external peripheral proteins
SRP
-signal recognition particle
-integral proteins
Transporter associated with sec system
-SecYEG, three proteins associated: Y, E, and G
-how proteins get transported outside of the cell
-requires energy
Tat pathway
-bacterial
-Twin Arginine Translocase
-mediated by proton motive force
-deliver folded proteins
-depend on a signal peptide (Twin arginine residues)
Tat pathway signal peptides are recognized by:
-TatBC becomes bound, then Tat A oligomerizes into a pore
oligomerizes
interaction of more than one polypeptide chain
The cell wall
needed by most prokaryotes
fucntions of the cell wall
-protect cell from osmotic lysis
-determine shape of cell
-protect against toxic substances
-contributes to pathogenicity
-active site for several antibiotics
antibiotics that funtion within the cell wall
-penicillin
-cephalosporins
-vancomycin
bacterial cell wall
-comprised of peptidoglycan (peptide and sugar)
-two glycan chains connected by peptide crosslinks containing 4 amino acids
two sugars that make up the glycan chain
-NAM
-NAG
