1Q95

Aspartate Transcarbamylase (ATCase) of Escherichia coli: A New Crystalline R State Bound to PALA, or to Product Analogues Phosphate and Citrate

Summary for 1Q95

• Entry DOI: 10.2210/pdb1q95/pdb
• Descriptor: Aspartate carbamoyltransferase catalytic chain, Aspartate carbamoyltransferase regulatory chain, N-(PHOSPHONACETYL)-L-ASPARTIC ACID, ... (5 entities in total)
• Functional Keywords: aspartate transcarbamylase, aspartate carbamoyltransferase, n-carbamyl-l-aspartate, pala, atcase-pala complex, r state, transferase
• Biological source: Escherichia coli; More
• Total number of polymer chains: 12
• Total formula weight: 310807.55

Authors

Huang, J.,Lipscomb, W.N. (deposition date: 2003-08-22, release date: 2004-06-08, Last modification date: 2023-08-16)

Primary citation

Huang, J.,Lipscomb, W.N.
Aspartate Transcarbamylase (ATCase) of Escherichia coli: A New Crystalline R-State Bound to PALA, or to Product Analogues Citrate and Phosphate
Biochemistry, 43:6415-6421, 2004

PubMed Abstract: Structures of the R-state of Escherichia coli ATCase maintained with carbamyl phosphate and succinate, phosphonoacetamide and malonate, or N-phosphonacetyl-l-aspartate (PALA) have previously been made in the space group P321, in which the two independent r (regulatory) and two independent c (catalytic) chains are repeated by crystallographic symmetry to yield the holoenzyme c(6)r(6), ((c(3))(2)(r(2))(3)). The exploration of a new crystalline R-state P2(1)2(1)2(1) was undertaken to examine the c(3).c(3) expansion of 11 A in the T-to-R transition, and to further test whether intermolecular contacts influence the binding of PALA. The results show that the expansion along the 3-fold axis is 10 A, and that the binding modes of the six crystallographic independent PALA molecules are virtually identical to one another, and to modes described previously. As further test, the PALA, a bisubstrate analogue, was displaced by citrate and phosphate, where citrate is an analogue of product carbamylaspartate. The results support the conclusions about the binding of the three previously studied analogues, and further support, within about 0.5 A, the structure proposed for the transition state [Gouaux, J. E., Krause, K. L., and Lipscomb, W. N. (1987) Biochem. Biophys. Res. Commun. 142, 893-897; Jin, L., Stec, B., Lipscomb, W. N., and Kantrowitz, E. R. (1999) Proteins: Struct., Funct., Genet. 37, 729-742].

PubMed: 15157075
DOI: 10.1021/bi030213b

Experimental method

X-RAY DIFFRACTION (2.46 Å)