PMID- 10080891
OWN - NLM
STAT- MEDLINE
DCOM- 19990428
LR  - 20190523
IS  - 0022-2836 (Print)
IS  - 0022-2836 (Linking)
VI  - 287
IP  - 2
DP  - 1999 Mar 26
TI  - A mutation that uncouples allosteric regulation of carbamyl phosphate synthetase 
      in Drosophila.
PG  - 277-85
AB  - In animals, UTP feedback inhibition of carbamyl phosphate synthetase II (CPSase) 
      controls pyrimidine biosynthesis. Suppressor of black (Su(b) or rSu(b)) mutants 
      of Drosophila melanogaster have elevated pyrimidine pools, and this mutation has 
      been mapped to the rudimentary locus. We report that rSu(b) is a missense 
      mutation resulting in a glutamate to lysine substitution within the second ATP 
      binding site (i.e. CPS.B2 domain) of CPSase. This residue corresponds to Glu780 
      in the Escherichia coli enzyme (Glu1153 in hamster CAD) and is universally 
      conserved among CPSases. When a transgene expressing the Glu-->Lys substitution 
      was introduced into Drosophila lines homozygous for the black mutation, the 
      resulting flies exhibited the Su(b) phenotype. Partially purified CPSase from 
      rSu(b) and transgenic flies carrying this substitution exhibited a dramatic 
      reduction in UTP feedback inhibition. The slight UTP inhibition observed with the 
      Su(b) enzyme in vitro was due mainly to chelation of Mg2+ by UTP. However, the Km 
      values for glutamate, bicarbonate, and ATP obtained from the Su(b) enzyme were 
      not significantly different from wild-type values. From these experiments, we 
      conclude that this residue plays an essential role in the UTP allosteric 
      response, probably in propagating the response between the effector binding site 
      and the ATP binding site. This is the first CPSase mutation found to abolish 
      feedback inhibition without significantly affecting other enzyme catalytic 
      parameters.
CI  - Copyright 1999 Academic Press.
FAU - Simmons, A J
AU  - Simmons AJ
AD  - Department of Microbiology & Immunology, Albert B. Chandler Medical Center & 
      Lucille P. Markey Cancer Center, University of Kentucky, Lexington, KY, 
      40536-0293, USA.
FAU - Rawls, J M
AU  - Rawls JM
FAU - Piskur, J
AU  - Piskur J
FAU - Davidson, J N
AU  - Davidson JN
LA  - eng
GR  - GM47644/GM/NIGMS NIH HHS/United States
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PT  - Research Support, U.S. Gov't, Non-P.H.S.
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - Netherlands
TA  - J Mol Biol
JT  - Journal of molecular biology
JID - 2985088R
RN  - 0 (Drosophila Proteins)
RN  - 0 (Insect Proteins)
RN  - 0 (Multienzyme Complexes)
RN  - 8L70Q75FXE (Adenosine Triphosphate)
RN  - EC 6.3.4.16 (Carbamoyl-Phosphate Synthase (Ammonia))
RN  - EC 6.3.4.16 (r protein, Drosophila)
RN  - EC 6.3.5.5 (Carbamoyl-Phosphate Synthase (Glutamine-Hydrolyzing))
RN  - I38ZP9992A (Magnesium)
RN  - UT0S826Z60 (Uridine Triphosphate)
SB  - IM
MH  - Adenosine Triphosphate/metabolism
MH  - Allosteric Regulation/genetics
MH  - Animals
MH  - Animals, Genetically Modified
MH  - Binding Sites/genetics
MH  - *Carbamoyl-Phosphate Synthase (Ammonia)
MH  - Carbamoyl-Phosphate Synthase (Glutamine-Hydrolyzing)/*genetics
MH  - Drosophila/*enzymology/genetics
MH  - *Drosophila Proteins
MH  - Feedback
MH  - Insect Proteins/*genetics
MH  - Kinetics
MH  - Magnesium/pharmacology
MH  - Multienzyme Complexes/*genetics
MH  - Mutation, Missense/genetics
MH  - Phenotype
MH  - Sequence Alignment
MH  - Sequence Analysis, DNA
MH  - Uridine Triphosphate/pharmacology
EDAT- 1999/03/19 00:00
MHDA- 1999/03/19 00:01
CRDT- 1999/03/19 00:00
PHST- 1999/03/19 00:00 [pubmed]
PHST- 1999/03/19 00:01 [medline]
PHST- 1999/03/19 00:00 [entrez]
AID - S0022-2836(99)92618-9 [pii]
AID - 10.1006/jmbi.1999.2618 [doi]
PST - ppublish
SO  - J Mol Biol. 1999 Mar 26;287(2):277-85. doi: 10.1006/jmbi.1999.2618.