Recombinant Escherichia coli Aquaporin Z (aqpZ) (Active)

Aquaporin Z (AqpZ) is an integral membrane protein found in Escherichia coli and Synechocystis sp. PCC 6803, which functions as a water-permeable channel in the plasma membrane [1]. It is a tetrameric protein that forms water channels in the cell membrane of Escherichia coli [2]. AqpZ plays a crucial role in the transport of water across Escherichia coli cells with a high rate [3]. Additionally, it is involved in cell volume regulation and sensitivity to osmotic stress in Synechocystis sp. PCC 6803 [4]. The physiological role of AqpZ includes its involvement in the short- and long-term osmoregulatory response and its requirement by rapidly growing cells [5]. Furthermore, AqpZ is highly stable and has negligible permeability to glycerol [6]. It has been shown to selectively conduct only water at high rates [7].

The molecular water transporter AqpZ remained elusive until its discovery, and the regulation of the aqpZ gene expression and the physiological function of the AqpZ protein are still not fully understood [8]. However, studies have shown that AqpZ is a specific biological water channel with high osmotic water permeability, lack of N-linked glycan, resistance to proteolysis, and is not inhibited by any biological macromolecules [9]. This makes AqpZ-based water recovery technology a promising prospect for water filtration and recovery, especially for space flight applications [9].

References:
[1] M. Akai, K. Onai, M. Kusano, M. Sato, H. Redestig, K. Toyookaet al., "Plasma membrane aquaporin aqpz protein is essential for glucose metabolism during photomixotrophic growth of synechocystis sp. pcc 6803", Journal of Biological Chemistry, vol. 286, no. 28, p. 25224-25235, 2011. https://doi.org/10.1074/jbc.m111.236380
[2] G. Hu, L. Chen, & J. Wang, "Insights into the mechanisms of the selectivity filter of escherichia coli aquaporin z", Journal of Molecular Modeling, vol. 18, no. 8, p. 3731-3741, 2012. https://doi.org/10.1007/s00894-012-1379-2
[3] Y. Zhao, H. Xie, L. Wang, Y. Shen, W. Chen, B. Songet al., "Gating mechanism of aquaporin z in synthetic bilayers and native membranes revealed by solid-state nmr spectroscopy", Journal of the American Chemical Society, vol. 140, no. 25, p. 7885-7895, 2018. https://doi.org/10.1021/jacs.8b03446
[4] M. Akai, K. Onai, M. Morishita, H. Mino, T. Shijuku, H. Maruyamaet al., "Aquaporin aqpz is involved in cell volume regulation and sensitivity to osmotic stress in synechocystis sp. strain pcc 6803", Journal of Bacteriology, vol. 194, no. 24, p. 6828-6836, 2012. https://doi.org/10.1128/jb.01665-12
[5] G. Calamita, "The escherichia coli aquaporin‐z water channel", Molecular Microbiology, vol. 37, no. 2, p. 254-262, 2000. https://doi.org/10.1046/j.1365-2958.2000.02016.x
[6] D. Kozono, X. Ding, I. Iwasaki, X. Meng, Y. Kamagata, P. Agreet al., "Functional expression and characterization of an archaeal aquaporin", Journal of Biological Chemistry, vol. 278, no. 12, p. 10649-10656, 2003. https://doi.org/10.1074/jbc.m212418200
[7] D. Savage, P. Egea, Y. Robles-Colmenares, J. O’Connell, & R. Stroud, "Architecture and selectivity in aquaporins: 2.5 å x-ray structure of aquaporin z", Plos Biology, vol. 1, no. 3, p. e72, 2003. https://doi.org/10.1371/journal.pbio.0000072
[8] G. Calamita, B. Kempf, M. Bonhivers, W. Bishai, E. Bremer, & P. Agre, "Regulation of the escherichia coli water channel gene aqpz", Proceedings of the National Academy of Sciences, vol. 95, no. 7, p. 3627-3631, 1998. https://doi.org/10.1073/pnas.95.7.3627
[9] J. Lian, X. Fang, J. Cai, Q. Chen, Q. Zheng, K. Louet al., "Efficient expression of membrane-bound water channel protein (aquaporin z) in escherichia coli", Protein and Peptide Letters, vol. 15, no. 7, p. 687-691, 2008. https://doi.org/10.2174/092986608785133717