Magnesium interactions with a CX26 connexon in lipid bilayers

  • Juan M. R. Albano
  • Julio C. Facelli
  • Marta B. FerraroEmail author
  • Monica Pickholz
Original Paper
Part of the following topical collections:
  1. QUITEL 2018 (44th Congress of Theoretical Chemists of Latin Expression)


Following our previous work, where we described the interaction of calcium with the Cx26 hemichannel, we further explore the same system by atomistic molecular dynamics simulations considering a different di-cation, magnesium. Specifically, the interaction of magnesium di-cation with the previously reported calcium binding sites (ASP2, ASP117, ASP159, GLU114, GLU119, GLU120, and VAL226) was investigated to identify similarities and differences between them. In order to do so, four extensive simulations were carried out. Two of them considered a Cx26 hemichannel embedded on a POPC bilayer with one of the di-cations and a sodium-chlorine solution. For the remaining two, no di-cations were included and a sodium-chlorine or potassium-chlorine solution was considered. Potassium has a similar atomic mass to calcium, and sodium to magnesium, but they both differ in charge (1e and 2e respectively). Magnesium and calcium, even having the same charge, showed different affinity for the explored protein. From the calcium binding sites referred above, we found that the magnesium di-cations only binds strongly to the GLU114 site of one connexin. For the sodium and potassium simulations, no specific interactions with the protein were found. Altogether, these results suggest that mass and steric effects play an important role in determining cation binding to Cx26 hemichannels.


Molecular dynamics CX26 Lipid bilayer Magnesium Connexins Calcium 


Funding information

The Center for High Performance Computing at The Utah University provided computer resources for High Performance Computing, which has been partially funded by the NIH Shared Instrumentation Grant 1S10OD021644-01A1. JCF has been partially supported by the University of Utah Center for Clinical and Translational Science under NCATS Grant U01TR002538. MBF has been partially supported by the University of Buenos Aires Grant 20020170100456BA and PIP CONICET 11220130100377. JMRA has been partially supported by the Florencio Fiorini Foundation. MP has been partially supported by grants ANPCyT PICT2014- 3653, PIP CONICET0131-2014.

Supplementary material

894_2019_4121_MOESM1_ESM.pdf (61 kb)
ESM 1 (PDF 60.6 kb)


  1. 1.
    Trosko JE, Ruch RJ (1998) Cell-cell communication in carcinogenesis. Front Biosci 3:d208–d236. CrossRefPubMedGoogle Scholar
  2. 2.
    Vinken MB, Vanhaecke T, Papeleu P et al (2006) Connexins and their channels in cell growth and cell death. Cell Signal 18:592–600. CrossRefPubMedGoogle Scholar
  3. 3.
    Vinken M (2015) Introduction: connexins, pannexins and their channels as gatekeepers of organ physiology. Cell Mol Life Sci 72:2775–2778. CrossRefPubMedPubMedCentralGoogle Scholar
  4. 4.
    Evans WH, Martin PEM (2002) Gap junctions: structure and function (Review). Mol Membr Biol 19:121–136. CrossRefPubMedGoogle Scholar
  5. 5.
    Peracchia C (2004) Chemical gating of gap junction channels: roles of calcium, pH and calmodulin. Biochim Biophys Acta Biomembr 1662:61–80. CrossRefGoogle Scholar
  6. 6.
    Pantano S, Zonta F, Mammano F (2008) A fully atomistic model of the Cx32 connexon. PLoS One 3:1–11. CrossRefGoogle Scholar
  7. 7.
    Yeager M, Harris AL (2007) Gap junction channel structure in the early 21st century: facts and fantasies. Curr Opin Cell Biol 19:521–528. CrossRefPubMedPubMedCentralGoogle Scholar
  8. 8.
    Bennett MVL, Contreras JE, Bukauskas FF, Sáez JC (2003) New roles for astrocytes: gap junction hemichannels have something to communicate. Trends Neurosci 26:610–617CrossRefGoogle Scholar
  9. 9.
    Hung A, Yarovsky I (2011) Gap junction hemichannel interactions with zwitterionic lipid, anionic lipid, and cholesterol: molecular simulation studies. Biochemistry 50:1492–1504. CrossRefPubMedGoogle Scholar
  10. 10.
    Lopez W, Ramachandran J, Alsamarah A et al (2016) Mechanism of gating by calcium in connexin hemichannels. Proc Natl Acad Sci 201609378. CrossRefGoogle Scholar
  11. 11.
    Zonta F, Polles G, Zanotti G, Mammano F (2012) Permeation pathway of homomeric connexin 26 and connexin 30 channels investigated by molecular dynamics. J Biomol Struct Dyn 29:985–998. CrossRefPubMedPubMedCentralGoogle Scholar
  12. 12.
    Zhang Y, Tang W, Ahmad S et al (2005) Gap junction-mediated intercellular biochemical coupling in cochlear supporting cells is required for normal cochlear functions. Proc Natl Acad Sci U S A 102:15201–15206. CrossRefPubMedPubMedCentralGoogle Scholar
  13. 13.
    Ebihara L, Steiner E (1993) Properties of a nonjunctional current expressed from a rat connexin46 cDNA in Xenopus oocytes. J Gen Physiol 102:59–74CrossRefGoogle Scholar
  14. 14.
    Albano JMRJMR, Mussini N, Toriano R et al (2018) Calcium interactions with Cx26 hemmichannel: Spatial association between MD simulations biding sites and variant pathogenicity. Comput Biol Chem 77:331–342. CrossRefPubMedGoogle Scholar
  15. 15.
    Bennett BC, Purdy MD, Baker KA et al (2016) An electrostatic mechanism for Ca(2+)-mediated regulation of gap junction channels. Nat Commun 7:8770. CrossRefPubMedPubMedCentralGoogle Scholar
  16. 16.
    Beyer EC, Berthoud VM (2017) Gap junction structure: unraveled, but not fully revealed. F1000Research 6:568. CrossRefPubMedPubMedCentralGoogle Scholar
  17. 17.
    Ebihara L, Liu X, Pal JD (2003) Effect of external magnesium and calcium on human connexin46 hemichannels. Biophys J 84:277–286. CrossRefPubMedPubMedCentralGoogle Scholar
  18. 18.
    Cernak I, Radosevic P, Malicevic Z, Savic J (1995) Experimental magnesium depletion in adult rabbits caused by blast overpressure. Magnes Res 8:249–259PubMedGoogle Scholar
  19. 19.
    Heath DL, Vink R (1996) Traumatic brain axonal injury produces sustained decline in intracellular free magnesium concentration. Brain Res 738:150–153CrossRefGoogle Scholar
  20. 20.
    Murphy E, Steenbergen C, Levy LA et al (1989) Cytosolic free magnesium levels in ischemic rat heart. J Biol Chem 264:5622–5627PubMedGoogle Scholar
  21. 21.
    Helpern JA, Vande Linde AM, Welch KM et al (1993) Acute elevation and recovery of intracellular [Mg2+] following human focal cerebral ischemia. Neurology 43:1577–1581CrossRefGoogle Scholar
  22. 22.
    Wood I, Albano JMR, Filho PLO et al (2018) A sumatriptan coarse-grained model to explore different environments: interplay with experimental techniques. Eur Biophys J 47:561–571. CrossRefPubMedGoogle Scholar
  23. 23.
    Calì T, Frizzarin M, Luoni L et al (2017) The ataxia related G1107D mutation of the plasma membrane Ca2 + ATPase isoform 3 affects its interplay with calmodulin and the autoinhibition process. Biochim Biophys Acta Mol basis Dis 1863:165–173. CrossRefPubMedGoogle Scholar
  24. 24.
    Zonta F, Buratto D, Crispino G et al (2018) Cues to opening mechanisms from in silico electric field excitation of Cx26 hemichannel and in vitro mutagenesis studies in HeLa Transfectans. Front Mol Neurosci 11.
  25. 25.
    Abraham MJ, Murtola T, Schulz R et al (2015) Gromacs: High performance molecular simulations through multi-level parallelism from laptops to supercomputers. SoftwareX 1–2:19–25. CrossRefGoogle Scholar
  26. 26.
    Best RB, Zhu X, Shim J et al (2012) Optimization of the additive CHARMM all-atom protein force field targeting improved sampling of the backbone ϕ, ψ and side-chain χ 1 and χ 2 dihedral angles. J Chem Theory Comput 8:3257–3273. CrossRefPubMedPubMedCentralGoogle Scholar
  27. 27.
    Albano JMR, de Paula E, Pickholz M (2018) Molecular dynamics simulations to study drug delivery systems. Molecular Dynamics. InTech. Google Scholar
  28. 28.
    Wu Y, Tepper HL, Voth GA (2006) Flexible simple point-charge water model with improved liquid-state properties. J Chem Phys 124:024503. CrossRefPubMedGoogle Scholar
  29. 29.
    Mahoney MW, Jorgensen WL (2000) A five-site model for liquid water and the reproduction of the density anomaly by rigid, nonpolarizable potential functions. J Chem Phys 112:8910. CrossRefGoogle Scholar
  30. 30.
    Nosé S (1984) A unified formulation of the constant temperature molecular dynamics methods. J Chem Phys 81:511. CrossRefGoogle Scholar
  31. 31.
    Hoover WG (1985) Canonical dynamics: equilibrium phase-space distributions. Phys Rev A 31:1695–1697. CrossRefGoogle Scholar
  32. 32.
    Parrinello M, Rahman A (1982) Strain fluctuations and elastic constants. J Chem Phys 76:2662–2666. CrossRefGoogle Scholar
  33. 33.
    Ewald PP (1921) Die berechnung Optischer und Elektrostatisher Gitterpotentiale. Ann Phys 64:253–287CrossRefGoogle Scholar
  34. 34.
    Herce HD, Garcia AE, Darden T (2007) The electrostatic surface term:(I) periodic systems. J Chem Phys 126:124106CrossRefGoogle Scholar
  35. 35.
    Hess B, Kutzner C, van der Spoel D, Lindahl E (2008) GROMACS 4: algorithms for highly efficient, load balanced, and scalable molecular simulations. J Chem Theory Comput 4:435–447CrossRefGoogle Scholar
  36. 36.
    Dolinsky TJ, Nielsen JE, McCammon JA, Baker NA (2004) PDB2PQR: an automated pipeline for the setup of Poisson-Boltzmann electrostatics calculations. Nucleic Acids Res 32:W665–W667. CrossRefPubMedPubMedCentralGoogle Scholar
  37. 37.
    Jo S, Kim T, Iyer V, Im W (2008) CHARMM GUI: a web based graphical user interface for CHARMM. J Comput Chem 29:1859–1865. CrossRefPubMedGoogle Scholar
  38. 38.
    Wu EL, Cheng X, Jo S et al (2014) CHARMM-GUI Membrane Builder toward realistic biological membrane simulations. J Comput Chem 35:1997–2004. CrossRefPubMedPubMedCentralGoogle Scholar
  39. 39.
    Albano JMR (2019) Structure: Cx26 hemichannel embedded in a POPC bilayer.
  40. 40.
    Humphrey W, Dalke A, Schulten K (1996) VMD: visual molecular dynamics. J Mol Graph 14:33–38. CrossRefPubMedPubMedCentralGoogle Scholar
  41. 41.
    Jones DE, Lund AM, Ghandehari H, Facelli JC (2016) Molecular dynamics simulations in drug delivery research: calcium chelation of G3.5 PAMAM dendrimers. Cogent Chem 2:1229830. CrossRefPubMedPubMedCentralGoogle Scholar

Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2019

Authors and Affiliations

  • Juan M. R. Albano
    • 1
    • 2
  • Julio C. Facelli
    • 3
  • Marta B. Ferraro
    • 1
    • 2
    Email author
  • Monica Pickholz
    • 1
    • 2
  1. 1.Departamento de Física, Facultad de Ciencias Exactas y NaturalesUniversidad de Buenos Aires and IFIBABuenos AiresArgentina
  2. 2.Instituto de Física de Buenos Aires (IFIBA)CONICET–Universidad de Buenos AiresBuenos AiresArgentina
  3. 3.Department of Biomedical InformaticsUniversity of UtahSalt Lake CityUSA

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