REGULATION OF ADENINE NUCLEOTIDE POOLS

Project: Research project

Project Details

Description

The pathway of AMP degradation in prokaryotic organisms involves hydrolysis
of the N-glycosidic bond of AMP by AMP nucleosidase. Regulation of this
enzyme in vivo appears to occur by allosteric MgATP activation, Pi
inhibition and a Pi induced dissociation. The pathway for AMP degradation
in eukaryotic organisms, involves AMP deaminase. AMP deaminase from yeast
is also under allosteric regulation by activation with ATP (and MgATP) and
by inhibition with Pi. No prokaryotes have been found to contain AMP
deaminase and no eukaryotes have been found to contain AMP nucleosidase.
The similarity of the proposed metabolic function and the allosteric
regulation of these two enzymes suggest that AMP deaminase may have evolved
from AMP nucleosidase. One goal of this project is to complete studies of
the regulation and the metabolic role of AMP degradation. Magnetic
resonance studies will be used to quantitate the ligands bound to Mn++ in
the MnATP-AMP nucleosidase complex. Studies of the mechanism of AMP
nucleosidase will be completed with the enzyme from Azotobacter
vinelandii. Metabolic studies will use E. coli mutants with deficiencies
in the enzymes of adenylate degradation. Special emphasis will be placed
on the regulation and role of AMP nucleosidase in in vivo experiments. The
metabolic consequences of adenylate regulation will be tested in mutants
deficient in this pathway. Another goal of this research is to determine
the primary sequence of AMP nucleosidase and AMP deaminase to gain
structural information on these regulatory enzymes and to test for possible
regions of sequence homology. The structure will be determined by
sequencing the structural genes which are to be cloned as plasmids in E.
coli K12. The structural gene for AMP nucleosidase will be amplified in E.
coli to create mutants which overproduce the enzyme.
StatusFinished
Effective start/end date12/31/8911/30/93

ASJC

  • Genetics
  • Molecular Biology
  • Medicine(all)
  • Biochemistry, Genetics and Molecular Biology(all)

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