2 transport of human aquaporin5 Xue Qin PI Walter F Boron Department of Physiology and Biophysics Case Western Reserve University Gas Channel Workshop Background Aquaporin 5 is a water channel highly expressed in salivary glands eye lung and trachea ID: 1006616
Download Presentation The PPT/PDF document "Structure determinants for CO" is the property of its rightful owner. Permission is granted to download and print the materials on this web site for personal, non-commercial use only, and to display it on your personal computer provided you do not modify the materials and that you retain all copyright notices contained in the materials. By downloading content from our website, you accept the terms of this agreement.
1. Structure determinants for CO2 transport of human aquaporin5Xue Qin PI: Walter F BoronDepartment of Physiology and BiophysicsCase Western Reserve UniversityGas Channel Workshop
2. BackgroundAquaporin 5 is a water channel highly expressed in salivary glands, eye, lung and trachea.Aquaporins are composed of 6 transmembrane domains, with N- and C- terminus on the cytoplasmic side of the membrane. Fig 5Topology of AQP1H2N124563COOHRepeated NPA motifsAEBCD
3. Background H2O permeability2 filter regions is important for H2O transportSelectivity filter: ar/R regionNPA regionCO2 permeabilityNot well definedHorsefield et al, 2008 PNASnn
4. H2O permeability--PfCO2 permeability--pHSVolumetric assay to measure osmotic water permeabilityHow fast the volume of oocytes change with timeMicroelectrode to measure pH on the surface of the oocytesMethods
5. OutlineI Amino acids at the mouth of the central poreII Amino acids lining the central pore
6. OutlineI Amino acids at the mouth of the central poreII Amino acids lining the central pore
7. water porecentral pore
8.
9. 3
10. D50T41L43V52Protein sequence alignment
11. bAQP1hAQP5
12. H2OhAQP5T41YT41WT41FT41G0.0000.0010.0020.0030.004Pf (cm/s)
13. 050100150200hAQP5T41YhAQP5T41WhAQP5T41FhAQP5T41GRelative channel-dependent CO2 permeability
14. L43T41
15. T41YT41Y
16. T41WT41W
17. T41F
18. T41G
19. Conclusion II Amino acids at the mouth of the central poreChanges of pHS (CO2 permeability) is more sensitive than Pf (H2O permeability)T41 is more important than L43.II Amino acids lining the central pore
20. OutlineI Amino acids at the mouth of the central poreII Amino acids lining the central pore
21. Amino acids lining the central poreT41L43L47L51L167L163G159
22. Sequence alignment of AQPsTM2TM5
23. If mutate to Asp (D)T41L43L47L51L167DDDDD
24. Channel-dependent pHS for CO20.000.030.060.09hAQP5 T41DhAQP5 L43DhAQP5 L47DhAQP5 L51DhAQP5 L167DLXXD − pHS*Pf*Aspartic Acid (Asp)
25. Channel-dependent Pf (cm/s)0.0000.0010.0020.0030.004H2OhAQP5 T41DhAQP5 L43DhAQP5 L47DhAQP5 L51DhAQP5 L167DLXXD − Pf*Aspartic Acid (Asp)
26. If mutate to Arg (R)T41L43L47L51L167RRRRR
27. -0.020.000.020.040.060.080.100.12hAQP5 T41RhAQP5 L43RhAQP5 L47RhAQP5 L51RhAQP5 L167RChannel-dependent pHS for CO2LXXR − pHS*Arginine (Arg)Pf*
28. Channel-dependent Pf (cm/s)0.0000.0010.0020.0030.004H2OhAQP5 T41RhAQP5 L43RhAQP5 L47RhAQP5 L51RhAQP5 L167RLXXR − Pf*Arginine (Arg)
29. If mutate to Thr (T)T41L43L47L51L167TTTTT
30. Channel-dependent pHS for CO20.000.030.060.09hAQP5 T41wt AQP5hAQP5 L43ThAQP5 L47ThAQP5 L51ThAQP5 L167TLXXT − pHS*Threonine (Thr)Pf*
31. Channel-dependent Pf (cm/s)0.0000.0010.0020.0030.004H2OhAQP5 T41ThAQP5 L43ThAQP5 L47ThAQP5 L51ThAQP5 L167TLXXT − Pf*Threonine (Thr)L163T
32. Conclusion III Amino acids at the mouth of the central poreChanges of pHS (CO2 permeability) is more sensitive than Pf (H2O permeability)T41 is more important than L43.II Amino acids lining the central poreChanges of Pf (H2O permeability) is more sensitive than pHS (CO2 permeability) Of all the amino acids lining the central pore, L51 is most sensitive to determine Pf and pHS.
33. AcknowledgementCollaboratorEmad TajkhorshidLabWalter F BoronRaif Musa-AzizMark D Parker