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PRESENTATION
II NAME
Dihydrofolate Reductase
Beta lactmase
p300
Macrophage Infectivity Potentiator
By Christine Harvey
Dihydrofolate Reductase
in Escherichia coli
• Class: oxidoreductase
• Reduces dihydrofolate (DHF) to
tetrahydrofolate (THF)
• THF is a precursor to amino acids, purine and
thymidylate.
• DHFR is imperative to cell life
http://en.wikipedia.org/wiki/DHFR
Function
Source: Schweitzer, Barry I., et al. The FASEB Journal Vol 4, “Dihydrofolate reductase as a therapeutic target.” May 1990.
Mechanism
http://en.wikipedia.org/wiki/DHFR
Structure
Binding Pocket
MOVIE
Sequence Alignment
Phylogenetic Tree
Beta-Lactamase
in Escherichia coli
• Class: Hydrolase
• Beta Lactamase is produce by bacteria after
being exposed to beta lactam antibiotics
• Responsible for beta lactam antibiotic resistance
Penicillin
• Contains beta lactam
ring
Mechanism
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p300
In Homo Sapiens
• Class: Transferase
• p300 transfers an acetyl group from acetyl
coenzyme A to an active site lysine
• Transcriptional activation occurs upon
acetyl transfer
Title
• p300 is responsible for cell growth before and after
birth
• Cancer suppressor
Domains
Taz2
KIX
Bromodomain
HAT
Zinc Fingers (3)
Taz2
Creb
Histone Acetyl Transferase
• Active site tyrosine acts as nucleophile
Source: http://www.bmolchem.wisc.edu/labs/denu/images/hats/sequential.jpg
Docking
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Macrophage Infectivity
Potentiator
in Legionella
pneumophila
Legionella pneumophila
• gram negative bacteria
• Causes Legionnaires’ disease
• Carried in aerosols from man-made water
systems
MIP
• Class: Isomerase
• Catalyzes the isomeration of the Nterminal on proline
• Cause of virulence in Legionnaires’
disease
• Located on outer membrane protein
Crystalization
• Solution: 100 mM MES (pH 6.1–6.5), 15–20% (w/v) PEG
8000 and 500 mM zinc acetate. Protein concentration was
10 mg ml–1in 20 mM HEPES, pH 7.0
• Crystals were grown for 2-3 weeks at 288K
• X-ray data was collected at 100K in a nitrogen gas stream
(dried paraffin oil) at 2.4 Angstrom resolution
• Multiwavelength anomalous dispersion (MAD) with zinc
was used for phasing
Source: Riboldi-Tunnicliffe, Alan et al., Nature Structural Biology, vol.8:
9. “Crystal structure of Mip, a prolylisomerase from Legionella
pneumophila.” September 2001.
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Mechanism
• Peptidyl-prolyl cis-trans isomerases’
(PPIases) mechanism is not currently
know
Source: Park, Steven T., et al. Journal of Biological Chemistry. Vol. 267 No.5, “PPIase Catalysis by Human Fk506-binding Protein Proceeds Through
a Conformational Twist Mechanism.” February 1992.
Source: Riboldi-Tunnicliffe, Alan et al., Nature Structural Biology, vol.8: 9. “Crystal structure of Mip, a prolylisomerase from
Legionella pneumophila.” September 2001.
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Questions?
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