1t4b

Publication Abstract from PubMed

Two high-resolution structures have been determined for Eschericia coli aspartate beta-semialdehyde dehydrogenase (ecASADH), an enzyme of the aspartate biosynthetic pathway, which is a potential target for novel antimicrobial drugs. Both ASADH structures were of the open form and were refined to 1.95 A and 1.6 A resolution, allowing a more detailed comparison with the closed form of the enzyme than previously possible. A more complex scheme for domain closure is apparent with the subunit being split into two further sub-domains with relative motions about three hinge axes. Analysis of hinge data and torsion-angle difference plots is combined to allow the proposal of a detailed structural mechanism for ecASADH domain closure. Additionally, asymmetric distortions of individual subunits are identified, which form the basis for the previously reported "half-of-the-sites reactivity" (HOSR). A putative explanation of this arrangement is also presented, suggesting the HOSR system may provide a means for ecASADH to offset the energy required to remobilise flexible loops at the end of the reaction cycle, and hence avoid falling into an energy minimum.

High-resolution structures reveal details of domain closure and "half-of-sites-reactivity" in Escherichia coli aspartate beta-semialdehyde dehydrogenase.,Nichols CE, Dhaliwal B, Lockyer M, Hawkins AR, Stammers DK J Mol Biol. 2004 Aug 13;341(3):797-806. PMID:15288787^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.