| Structural highlights
Function
[KDGA_SULSF] Involved in the degradation of glucose and galactose via the Entner-Doudoroff pathway. Catalyzes the reversible cleavage of 2-keto-3-deoxy-6-phosphogluconate (KDPG) and 2-keto-3-deoxygluconate (KDG) forming pyruvate and glyceraldehyde 3-phosphate or glyceraldehyde, respectively. It is also able to catalyze the reversible cleavage of 2-keto-3-deoxy-6-phosphogalactonate (KDPGal) and 2-keto-3-deoxygalactonate (KDGal). It is equally active with both D- and L-glyceraldehyde.[1] [2] [3]
Publication Abstract from PubMed
The thermoacidophilic archaea Picrophilus torridus and Sulfolobus solfataricus catabolize glucose via a nonphosphorylative Entner-Doudoroff pathway and a branched Entner-Doudoroff pathway, respectively. Key enzymes for these Entner-Doudoroff pathways are the aldolases, 2-keto-3-deoxygluconate aldolase (KDG-aldolase) and 2-keto-3-deoxy-6-phosphogluconate aldolase [KD(P)G-aldolase]. KDG-aldolase from P. torridus (Pt-KDG-aldolase) is highly specific for the nonphosphorylated substrate, 2-keto-3-deoxygluconate (KDG), whereas KD(P)G-aldolase from S. solfataricus [Ss-KD(P)G-aldolase] is an enzyme that catalyzes the cleavage of both KDG and 2-keto-3-deoxy-6-phosphogluconate (KDPG), with a preference for KDPG. The structural basis for the high specificity of Pt-KDG-aldolase for KDG as compared to the more promiscuous Ss-KD(P)G-aldolase has not been analyzed before. In this work, we report the elucidation of the structure of Ss-KD(P)G-aldolase in complex with KDPG at 2.35 A and that of KDG-aldolase from P. torridus at 2.50 A resolution. By superimposition of the active sites of the two enzymes, and subsequent site-directed mutagenesis studies, a network of four amino acids, namely, Arg106, Tyr132, Arg237, and Ser241, was identified in Ss-KD(P)G-aldolase that interact with the negatively charged phosphate group of KDPG, thereby increasing the affinity of the enzyme for KDPG. This KDPG-binding network is absent in Pt-KDG-aldolase, which explains the low catalytic efficiency of KDPG cleavage.
Insights into the Substrate Specificity of Archaeal Entner-Doudoroff Aldolases: The Structures of Picrophilus torridus 2-Keto-3-deoxygluconate Aldolase and Sulfolobus solfataricus 2-Keto-3-deoxy-6-phosphogluconate Aldolase in Complex with 2-Keto-3-deoxy-6-phosphogluconate.,Zaitsev V, Johnsen U, Reher M, Ortjohann M, Taylor GL, Danson MJ, Schonheit P, Crennell SJ Biochemistry. 2018 Jun 13. doi: 10.1021/acs.biochem.8b00535. PMID:29812914[4]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Buchanan CL, Connaris H, Danson MJ, Reeve CD, Hough DW. An extremely thermostable aldolase from Sulfolobus solfataricus with specificity for non-phosphorylated substrates. Biochem J. 1999 Nov 1;343 Pt 3:563-70. PMID:10527934
- ↑ Lamble HJ, Heyer NI, Bull SD, Hough DW, Danson MJ. Metabolic pathway promiscuity in the archaeon Sulfolobus solfataricus revealed by studies on glucose dehydrogenase and 2-keto-3-deoxygluconate aldolase. J Biol Chem. 2003 Sep 5;278(36):34066-72. Epub 2003 Jun 24. PMID:12824170 doi:http://dx.doi.org/10.1074/jbc.M305818200
- ↑ Lamble HJ, Theodossis A, Milburn CC, Taylor GL, Bull SD, Hough DW, Danson MJ. Promiscuity in the part-phosphorylative Entner-Doudoroff pathway of the archaeon Sulfolobus solfataricus. FEBS Lett. 2005 Dec 19;579(30):6865-9. Epub 2005 Dec 1. PMID:16330030 doi:http://dx.doi.org/10.1016/j.febslet.2005.11.028
- ↑ Zaitsev V, Johnsen U, Reher M, Ortjohann M, Taylor GL, Danson MJ, Schonheit P, Crennell SJ. Insights into the Substrate Specificity of Archaeal Entner-Doudoroff Aldolases: The Structures of Picrophilus torridus 2-Keto-3-deoxygluconate Aldolase and Sulfolobus solfataricus 2-Keto-3-deoxy-6-phosphogluconate Aldolase in Complex with 2-Keto-3-deoxy-6-phosphogluconate. Biochemistry. 2018 Jun 13. doi: 10.1021/acs.biochem.8b00535. PMID:29812914 doi:http://dx.doi.org/10.1021/acs.biochem.8b00535
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