scholarly journals Role of an invariant lysine residue in folate binding on Escherichia coli thymidylate synthase: Calorimetric and crystallographic analysis of the K48Q mutant

2008 ◽  
Vol 40 (10) ◽  
pp. 2206-2217 ◽  
Author(s):  
Aldo A. Arvizu-Flores ◽  
Rocio Sugich-Miranda ◽  
Rodrigo Arreola ◽  
Karina D. Garcia-Orozco ◽  
Enrique F. Velazquez-Contreras ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Thymidylate Synthase ◽  
Crystallographic Analysis ◽  
Lysine Residue

scholarly journals Catalytic role of histidine 147 in Escherichia coli thymidylate synthase

1989 ◽  
Vol 264 (32) ◽  
pp. 19132-19137
Author(s):  
I K Dev ◽  
B B Yates ◽  
J Atashi ◽  
W S Dallas
Keyword(s):  
Escherichia Coli ◽  
Thymidylate Synthase ◽  
Catalytic Role

scholarly journals The contribution of methionine to the stability of the Escherichia coli MetNIQ ABC transporter-substrate binding protein complex

2015 ◽  
Vol 396 (9-10) ◽  
pp. 1127-1134 ◽  
Author(s):  
Phong T. Nguyen ◽  
Qi Wen Li ◽  
Neena S. Kadaba ◽  
Jeffrey Y. Lai ◽  
Janet G. Yang ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Complex Formation ◽  
Dissociation Constant ◽  
Binding Protein ◽  
Crystallographic Analysis ◽  
E Coli ◽  
Multiple Conformations ◽  
The Stability

Abstract Despite the ubiquitous role of ATP-binding cassette (ABC) importers in nutrient uptake, only the Escherichia coli maltose and vitamin B12 ABC transporters have been structurally characterized in multiple conformations relevant to the alternating access transport mechanism. To complement our previous structure determination of the E. coli MetNI methionine importer in the inward facing conformation (Kadaba et al. (2008) Science 321, 250–253), we have explored conditions stabilizing the outward facing conformation. Using two variants, the Walker B E166Q mutation with ATP+EDTA to stabilize MetNI in the ATP-bound conformation and the N229A variant of the binding protein MetQ, shown in this work to disrupt methionine binding, a high affinity MetNIQ complex was formed with a dissociation constant measured to be 27 nm. Using wild type MetQ containing a co-purified methionine (for which the crystal structure is reported at 1.6 Å resolution), the dissociation constant for complex formation with MetNI is measured to be ∼40-fold weaker, indicating that complex formation lowers the affinity of MetQ for methionine by this amount. Preparation of a stable MetNIQ complex is an essential step towards the crystallographic analysis of the outward facing conformation, a key intermediate in the uptake of methionine by this transport system.

scholarly journals Functional role of cysteine-146 in Escherichia coli thymidylate synthase.

1988 ◽  
Vol 85 (5) ◽  
pp. 1472-1476 ◽  
Author(s):  
I. K. Dev ◽  
B. B. Yates ◽  
J. Leong ◽  
W. S. Dallas
Keyword(s):  
Escherichia Coli ◽  
Thymidylate Synthase ◽  
Functional Role
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