Project: Research project

Project Details


Lysine 2,3-aminomutase catalyzes the interconversion of L-lysine and L-
beta-lysine. This reaction is the first committed step in the pathway that
allows Clostridia to use Lysine as a source of carbon, nitrogen, and
energy. Clostridia also use beta-L-lysine for the biosynthesis of a number
of antibiotics. Numerous studies indicate that several intermediates on
the reaction pathway contain carbon-centered radicals. The purpose of this
study is to determine how the enzyme in combination with its cofactors
(pyridoxal phosphate, an iron-sulfur cluster [Fe-S], and S-
adenosylmethionine (SAM)) generates these radicals. The working hypothesis
is that upon electron transfer to SAM from [Fe-S], SAM homolyzes to
generate methionine and a 5'-deoxyadenosyl radical (5'-dA.) which is
responsible for initiating catalysis. In order to test this model,
electron paramagnetic resonance and Mossbauer spectroscopies will be used
to assess a change in the oxidation state of the [Fe-S] during catalysis.
In addition, the kinetic competence of this change will be verified using
rapid kinetics methods. Lastly, analogs of SAM will be synthesized and
used as probes for communication between the [Fe-S] and SAM during the
cleavage event, as well as traps to assess the production of 5'-dA.. This
proposed radical generating system is also present in the ribonucleotide
reductase from anaerobically growing E. coli, as well as pyruvate formate
lyase, and research in this area may offer clues for new methods of
inhibiting anaerobic bacteria.
Effective start/end date9/1/962/28/99


  • National Institute of General Medical Sciences
  • National Institute of General Medical Sciences
  • National Institute of General Medical Sciences


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