Biochemical Evaluation of Rtt109 Inhibitor as a Potential Anti-Fungal Agent

Ref ID: 18773

Author:

J. Pupaibool, MD (Doctor of Medicine) – Infectious Diseases Fellow, T. J. Kottom, MS – Instructor in Biochem/Molecular Biology, A. H. Limper, MD – Professor;

Author address:

Mayo Clinic, Rochester, MN.

Full conference title:

52nd Annual ICAAC

Date: 9 September 2014

Abstract:

Background: To date, all clinically effective drugs for opportunistic fungi are limited because it is difficult to identify fungi-specific molecular targets with no adverse effects on humans. Rtt109 is a fungal histone acetyltransferase (HAT) which acetylates histone H3 lysine 56. It is essential for Saccharomyces cerevisiae to survive in the presence of DNA-damaging agents. Rtt109 is conserved among fungal species, but it is quite diverged from mammalian HATs. Thus, it may represent an attractive target for anti-fungal therapy. We evaluated biochemical activities of an Rtt109 inhibitor, GPHR32548, with Pneumocystis Rtt109 (PcRtt109) and Aspergillus Rtt109 (AsRtt109). Methods: We incubated 1 µg of PcRtt109 and AsRtt109 with different concentrations of GPHR32548 before adding chicken histone (H3/H4) tetramers and [3H]acetyl-coenzyme A. Reaction mixtures are spotted onto P-81 phosphocellulose paper filters. The paper filters were air-dried and washed, then the radioactivity of [3H]-acetylated histones was measured. We also resolved the reaction mixtures using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The gels were dried and exposed to films. Results: GPHR32548 inhibited PcRtt109 and AsRtt109 in a dose-dependent fashion as demonstrated by autoradiography of [3H]-acetylated histones and dose-response curves (Figure 1). IC50 for PcRtt109 and AsRtt109 are 38.64 and 22.91 µM, respectively. Conclusions: GPHR32548 was shown to inhibit all fungal Rtt109 tested. The inhibition was species-independent. The results of our preliminary study indicate that Rtt109 is a potential target for anti-fungal therapy.

Abstract Number: F-813

Conference Year: 2012

Link to conference website: NULL

New link: NULL

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