PRESENTATION II NAME

By Christine Harvey

Dihydrofolate Reductase Beta lactmasep300Macrophage Infectivity Potentiator

Dihydrofolate Reductase

in Escherichia coli

http://en.wikipedia.org/wiki/DHFR

• Class: oxidoreductase

• Reduces dihydrofolate (DHF) to tetrahydrofolate (THF)

• THF is a precursor to amino acids, purine and thymidylate.

• DHFR is imperative to cell life

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-Lactamasein 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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p300In 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 N-terminal on proline

• Cause of virulence in Legionnaires’ disease

• Located on outer membrane protein

• 25 kDa

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

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Source: Riboldi-Tunnicliffe, Alan et al., Nature Structural Biology, vol.8: 9. “Crystal structure of Mip, a prolylisomerase from Legionella pneumophila.” September 2001.

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?