Haijun Duan came to Auburn University in the Fall of 2008. He
joined the Goodwin laboratory in January 2009. Haijun is known
around the Department and the lab as "Diessel". Diessel contributed
to a number of aspects of our work on KatG. He evaluated a series of
intrasubunit interdomain interactions and their role in
maintaining active site structure and function. Diessel also
made a critical contribution to our understanding of the part that
peroxidatic electron donors play in stimulating the catalase
activity of KatG. By generating a series of E. coli
mutants lacking the peroxide defensive systems katE, katG,
and ahpCF (singly and in combination) and using a
completmentation strategy with MtKatG and catalase-inactive variants
thereof, Diessel was able to show that the peroxidatic electron
donor stimulatory effect protected intact cells from the toxic
effects of hydrogen peroxide. Most interestingly, katE katG
double mutant and katE katG ahpCF triple mutants were
protected from hydrogen peroxide-dependent toxicity when
complemented with the Mt katG gene, and this protective
effect was stimulated by the peroxidatic electron donors.
However, complentation with the Y229F katG gene afforded no
protection from hydrogen peroxide toxicity in the presence or
absence of peroxidatic electron donor. On November 10, 2014, Diessel
defended his dissertation entitled KatG as a Defense Against
Hydrogen Peroxide Toxicity: From a Redundant C-terminal Domain to
the Paradoxical Synergy of Two Mutually Antagonistic Activities.
Dr. Haijun Duan is now a postdoctoral associate in the laboratory of
Professor Anne-Frances Miller at the University of Kentucky.
Duan, H., Suh, S.-J., and Goodwin, D.
C. 2013. Mechanism for
stimulation of bacterial defenses against H2O2
by
peroxidatic electron donors.99th
Annual Southeastern Branch of American Society of Microbiology
Meeting (SEBASM),
Auburn University, AL
.
Duan, H., and Goodwin, D.2011.Essential
role of distant
interdomain interactions in H2O2
decomposition by
catalase-peroxidases.18th
Annual
Meeting of the Society for Free Radical Biology and Medicine,
Atlanta, GA.