Na+/K+ exchange switches the catalytic apparatus of potassium-dependent plant L-asparaginaseBejger, M., Imiolczyk, B., Clavel, D., Gilski, M., Pajak, A., Marsolais, F., Jaskolski, M.
(2014) Acta Crystallogr D Biol Crystallogr 70: 1854-1872
- PubMed: 25004963
- DOI: 10.1107/S1399004714008700
- Structures With Same Primary Citation
- PubMed Abstract:
- Crystal structure of plant asparaginase.
Michalska, K., Bujacz, G., Jaskolski, M.
(2006) J Mol Biol 360: 105
- Crystal structure of isoaspartyl aminopeptidase in complex with L-aspartate
Michalska, K., Brzezinski, K., Jaskolski, M.
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- Crystal packing of plant-type L-asparaginase from Escherichia coli
Michalska, K., Borek, D., Hernandez-Santoyo, A., Jaskolski, M.
(2008) Acta Crystallogr D Biol Crystallogr D64: 309
- The mechanism of autocatalytic activation of plant-type L-asparaginases
Michalska, K., Hernandez-Santoyo, A., Jaskolski, M.
(2008) J Biol Chem 283: 13388
- Structural aspects of L-asparaginases, their friends and relations
Michalska, K., Jaskolski, M.
(2006) Acta Biochim Pol 53: 627
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Borek, D., Michalska, K., Brzezinski, K., Kisiel, A., Podkowinski, J., Bonthron, D.T., Krowarsch, D., Otlewski, J., Jaskolski, M.
(2004) Eur J Biochem 271: 3215
- Crystallization and preliminary crystallographic studies of a new L-asparaginase encoded by Escherichia coli genome.
Borek, D., Jaskolski, M.
(2000) Acta Crystallogr D Biol Crystallogr D56: 1505
- Sequence analysis of enzymes with asparaginase activity
Borek, D., Jaskolski, M.
(2001) Acta Biochim Pol 48: 893
- Structures of apo and product-bound human L-asparaginase: insights into the mechanism of autoproteolysis and substrate hydrolysis
Nomme, J., Su, Y., Konrad, M., Lavie, A.
(2012) Biochemistry 51: 6816
- Free glicyne accelerates the autoproteolytic activation of human asparaginase
Su, Y., Karamitros, C.S., Nomme, J., McSorley, T., Konrad, M., Lavie, A.
(2013) Chem Biol 20: 533
Plant-type L-asparaginases, which are a subclass of the Ntn-hydrolase family, are divided into potassium-dependent and potassium-independent enzymes with different substrate preferences. While the potassium-independent enzymes have already been well ...
Plant-type L-asparaginases, which are a subclass of the Ntn-hydrolase family, are divided into potassium-dependent and potassium-independent enzymes with different substrate preferences. While the potassium-independent enzymes have already been well characterized, there are no structural data for any of the members of the potassium-dependent group to illuminate the intriguing dependence of their catalytic mechanism on alkali-metal cations. Here, three crystal structures of a potassium-dependent plant-type L-asparaginase from Phaseolus vulgaris (PvAspG1) differing in the type of associated alkali metal ions (K(+), Na(+) or both) are presented and the structural consequences of the different ions are correlated with the enzyme activity. As in all plant-type L-asparaginases, immature PvAspG1 is a homodimer of two protein chains, which both undergo autocatalytic cleavage to α and β subunits, thus creating the mature heterotetramer or dimer of heterodimers (αβ)2. The αβ subunits of PvAspG1 are folded similarly to the potassium-independent enzymes, with a sandwich of two β-sheets flanked on each side by a layer of helices. In addition to the `sodium loop' (here referred to as the `stabilization loop') known from potassium-independent plant-type asparaginases, the potassium-dependent PvAspG1 enzyme contains another alkali metal-binding loop (the `activation loop') in subunit α (residues Val111-Ser118). The active site of PvAspG1 is located between these two metal-binding loops and in the immediate neighbourhood of three residues, His117, Arg224 and Glu250, acting as a catalytic switch, which is a novel feature that is identified in plant-type L-asparaginases for the first time. A comparison of the three PvAspG1 structures demonstrates how the metal ion bound in the activation loop influences its conformation, setting the catalytic switch to ON (when K(+) is coordinated) or OFF (when Na(+) is coordinated) to respectively allow or prevent anchoring of the reaction substrate/product in the active site. Moreover, it is proposed that Ser118, the last residue of the activation loop, is involved in the potassium-dependence mechanism. The PvAspG1 structures are discussed in comparison with those of potassium-independent L-asparaginases (LlA, EcAIII and hASNase3) and those of other Ntn-hydrolases (AGA and Tas1), as well as in the light of noncrystallographic studies.
Center for Biocrystallographic Research, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Poland.