Assimilative Pathways, Peptidoglycan Synthesis, Cell Wall Inhibiting Antibiotics

What are anaplerotic reactions?

Reactions that replenish citric acid cycle intermediates

Why are anaplerotic reactions needed?

To keep TCA going

What are the 3 C4 reactions?

PEP + CO2 = OAA
Pyruvate + CO2 + NADPH = Malate + NADP+
Pyruvate + CO2 + ATP = OAA + ADP + Pi

What enzyme catalyzes PEP + CO2 = OAA?

PEP carboxylase

What enzyme catalyzes Pyruvate + CO2 + NADPH = Malate + NADP+

Malic enzyme

What enzyme catalyzes Pyruvate + CO2 + ATP = OAA + ADP + Pi

pyruvate carboxylase

The reaction Pyruvate + CO2 + ATP = OAA + ADP + Pi is the first step in what metabolic pathway?

Gluconeogenesis

What enzyme converts OAA into PEP in gluconeogenesis?

PEP carboxylase

What is the C3 pathway that we discussed?

RuBP goes to 3PG through RUBISCO

What is the difference between chemosynthesis and photosynthesis?

In chemosynthesis, the electrons used to make sugar come from other compounds such as hydrogen sulfide

Nitrogen fixation is catalyzed by what enzyme?

nitrogenase

Nitrogenase is inhibited by what molecule?

Oxygen

Nitrogenase reduces ___ to ___ using ____ and ____

N2 to NH4 using H+ and ATP

What does anammox stand for?

anaerobic ammonia oxidation

What occurs in an anammox reaction?

Ammonium ion is oxidised to N2

What occurs in assimilatory nitrate reduction and what enzyme is used?

Nitrate is converted into ammonia Nitrate reductase

What occurs in nitrification?

Ammonia is converted to nitrate

What occurs in dissimilatory nitrate reduction (denitrification)?

Nitrate is converted into N2

What serves to convert N2 into Organic N?

Nitrogen fixation

aminations convert alpha keto acids to alpha amino acids using ____ and ____.

NH4+ and energy

What enzyme converts a-ketoglutarate to glutamate?

Glutamate dehydrogenase (GDH)

GDH works when NH4+ is in _____ concentrations.

High

What enzyme converts glutamate into glutamine?

glutamine synthetase

Glutamine synthetase works well when NH4+ is in _____ concentrations

low

What enzyme converted aspartate into asparagine?

Asparagine synthetase

What does transaminations refer to?

Moving amino group

a-ketoglutarate and alanine form glutamate and pyruvate through_____.

Glutamate pyruvate transaminase

Glutamate and OAA form a-ketoglutarate and aspartate using what enzyme?

Gluatmate-OAA transaminase (GOT)

GOT requires this as a co-factor

pyridoxal phosphate

UDP is attached to N-acetylglucosamine-1-phosphate to form _____.

UDP-N-acetylglucosamine (UDP NAG)

What is the sequence of amino acids that build the pentapeptide onto UDP-NAM for gram-negative bacteria

L-alanine
D-glutamate
meso-diaminomelic acid
D-alanyl-D-alanine

What is the sequence of amino acids that build the pentapeptide onto UDP-NAM for gram-positive bacteria?

L-alanine
D-isoglutamate
Lysine
D-alanyl-D-alanine

To what amino acid penta glycine structure built onto in gram + bacteria?

Lysine

_____ is attached to Bactoprenol to form Lipid I

UDP NAM penta peptide

What is attached to NAM that forms lipid II?

UDP-NAG

NAM and NAG are held together by what type of bond?

Glycosidic linkage

What happens after the formation of Lipid II?

It is flipped from the cytoplasm into the periplasmic space

What breaks the glycosidic linkage between NAM and the Phosphate on Lipid II?

Altolisin

What enzyme moves the glycosidic linkage to existing peptidoglycan?

Transglycosylase

What enzyme promotes cross linking suing the pentapeptide?

Cross linking transpeptidase

What inhibits the removal of a phosphate from bactoprenol; thus, making it inactive?

Bacitracin

What inhibits peptidoglycan attaching to NAM?

Vancomycin

Penicillin comes from?

Mold

B-lactams are an analog of ______.

D-alanyl-D-alanine

How to beta lactams work?

They are a competitive inhibitor of transpeptidase. Prevent cross linking

What are the four types of beta lactams antibiotics?

Penicillins
Cephalosporins
Monobactams
Carbapenems

Penicillin is a ____ product.

Fungus

Cephalosporins are a ____ product

Fungus

Monobactams are a _____ product.

Bacterial

Carbapenems are a product from what organism?

Streptomyces

B-Lactams are degraded by what enzyme?

B-lactamases

What type of antibiotics are B-lactams and what are they especially good at eliminating?

Gram + (Streps and staph)

Methicillin is a type of ______.

Penicillin

MRSA (methicillin-resistant Staphylococcus aureus) is very resistant to antibiotics. What is the gene that encodes a low-affinity PBP?

mecA

mecA is found on a mobile gene cassette in MRSA. What is this cassette called?

SCCmec

What is a characteristic of Extended spectrum B-lactamases (ESBLs)

They exhibit a broader substrate specificity

How did ESBLs arise?

Point mutations in B-lactamase gene with subsequent selection by widespread antibiotic use.

What are two B-lactamase inhibtiors?

Clavulanic acid+amoxicillin
Sulbactam + ampicllin

What is Clavulanic acid+amoxicillin called?

Augmentin

What is Sulbactam + ampicillin called?

Unasym

What does Lantibiotics stand for?

Lanthionine-containing antibiotics

What are compounds produced and secreted by a bacterial species that is effective against competing bacterial species?

Bacteriocins

Bacteriocins are only effective against which type of bacteria?

Gram +

What type of lantibiotics is a PG synthesis inhibitor?

Type B

How do type B lantibiotics inhibit PG synthesis?

Binds to lipid II which prevents cross linking

Vancomycin is a _____ produced by ______.

Glycopeptide produced by streptomyces

How does vancomycin work?

inhibits transpeptidase activity by binding to the D-alanyl-D-alanine terminus of pentapeptide

Vancomycin Resistant Enterococcus (VRE) utilize this at the pentapeptide terminus.

D-alanyl-D-lactate

What produces bacitracin?

Bacillus subtilis

What produces cycloserine?

Streptomyces fliamentas

What two enzymes does cycloserine inhibit?

Alanine racemase
Alanine ligase

What does Moenomycin A inhibit?

Transglycosylase active site of PBP

What species produces Moenomycin?

Streptomyces