PMID- 10593947
OWN - NLM
STAT- MEDLINE
DCOM- 20000127
LR  - 20190508
IS  - 0021-9258 (Print)
IS  - 0021-9258 (Linking)
VI  - 274
IP  - 51
DP  - 1999 Dec 17
TI  - Interdomain signaling in glutamine phosphoribosylpyrophosphate amidotransferase.
PG  - 36498-504
AB  - The glutamine phosphoribosylpyrophosphate (PRPP) amidotransferase-catalyzed
      synthesis of phosphoribosylamine from PRPP and glutamine is the sum of two
      half-reactions at separated catalytic sites in different domains. Binding of PRPP
      to a C-terminal phosphoribosyltransferase domain is required to activate the
      reaction at the N-terminal glutaminase domain. Interdomain signaling was
      monitored by intrinsic tryptophan fluorescence and by measurements of glutamine
      binding and glutamine site catalysis. Enzymes were engineered to contain a single
      tryptophan fluorescence reporter in key positions in the glutaminase domain.
      Trp(83) in the glutamine loop (residues 73-84) and Trp(482) in the C-terminal
      helix (residues 471-492) reported fluorescence changes in the glutaminase domain 
      upon binding of PRPP and glutamine. The fluorescence changes were perturbed by
      Ile(335) and Tyr(74) mutations that disrupt interdomain signaling. Fluoresence
      titrations of PRPP and glutamine binding indicated that signaling defects
      increased the K(d) for glutamine but had little or no effect on PRPP binding. It 
      was concluded that the contact between Ile(335) in the phosphoribosyltransferase 
      domain and Tyr(74) in the glutamine site is a primary molecular interaction for
      interdomain signaling. Analysis of enzymes with mutations in the glutaminase
      domain C-terminal helix and a 404-420 peptide point to additional signaling
      interactions that activate the glutamine site when PRPP binds.
FAU - Bera, A K
AU  - Bera AK
AD  - Department of Biochemistry, Purdue University, West Lafayette, Indiana
      47907-1153, USA.
FAU - Chen, S
AU  - Chen S
FAU - Smith, J L
AU  - Smith JL
FAU - Zalkin, H
AU  - Zalkin H
LA  - eng
GR  - R37 DK042303/DK/NIDDK NIH HHS/United States
GR  - DK42303/DK/NIDDK NIH HHS/United States
GR  - GM 24658/GM/NIGMS NIH HHS/United States
PT  - Journal Article
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - United States
TA  - J Biol Chem
JT  - The Journal of biological chemistry
JID - 2985121R
RN  - 0 (Bacterial Proteins)
RN  - 7540-64-9 (Phosphoribosyl Pyrophosphate)
RN  - EC 2.4.2.14 (Amidophosphoribosyltransferase)
SB  - IM
MH  - Amidophosphoribosyltransferase/*chemistry/genetics/metabolism
MH  - Bacterial Proteins/chemistry/genetics/metabolism
MH  - Binding Sites
MH  - Enzyme Activation
MH  - Escherichia coli
MH  - Mutation
MH  - Phosphoribosyl Pyrophosphate/*chemistry/genetics/metabolism
MH  - Protein Binding
MH  - Structure-Activity Relationship
MH  - Substrate Specificity
EDAT- 1999/12/14 00:00
MHDA- 1999/12/14 00:01
CRDT- 1999/12/14 00:00
PHST- 1999/12/14 00:00 [pubmed]
PHST- 1999/12/14 00:01 [medline]
PHST- 1999/12/14 00:00 [entrez]
AID - 10.1074/jbc.274.51.36498 [doi]
PST - ppublish
SO  - J Biol Chem. 1999 Dec 17;274(51):36498-504. doi: 10.1074/jbc.274.51.36498.