A ‘toothpaste tube’ model for ion transport through trans-membrane channels
Cragg, Peter J.; Allen, Marcus C.; Steed, Jonathan W.; Chemical Communications  (1999) 553–; doi:10.1039/a808492k

data_7110405
_publ_section_title
;
 A &#x2018;toothpaste tube&#x2019; model for ion transport through
 trans-membrane channels
;
_journal_issue                   6
_journal_name_full               'Chemical Communications'
_journal_page_first              553
_journal_paper_doi               10.1039/a808492k
_journal_year                    1999
_chemical_formula_sum            'C56 H95 F12 N3 Na2 O12 P2'
_chemical_formula_weight         1338.27
_chemical_name_systematic
; 
 ? 
;
_space_group_IT_number           15
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  '-C 2yc'
_symmetry_space_group_name_H-M   'C 1 2/c 1'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL-97
_cell_angle_alpha                90.00
_cell_angle_beta                 111.811(2)
_cell_angle_gamma                90.00
_cell_formula_units_Z            8
_cell_length_a                   43.506(3)
_cell_length_b                   13.8660(11)
_cell_length_c                   24.2283(16)
_cell_measurement_reflns_used    n/a
_cell_measurement_temperature    120(2)
_cell_measurement_theta_max      n/a
_cell_measurement_theta_min      n/a
_cell_volume                     13569.5(17)
_computing_cell_refinement       DENZO-SMN
_computing_data_reduction        DENZO-SMN
_computing_molecular_graphics    'RES2INS (Barbour, 1998)'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      120(2)
_diffrn_measured_fraction_theta_full 0.935
_diffrn_measured_fraction_theta_max 0.935
_diffrn_measurement_device_type  KappaCCD
_diffrn_measurement_method       '2o phi frames'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'fine-focus sealed tube'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71070
_diffrn_reflns_av_R_equivalents  0.1179
_diffrn_reflns_av_sigmaI/netI    0.1354
_diffrn_reflns_limit_h_max       51
_diffrn_reflns_limit_h_min       -51
_diffrn_reflns_limit_k_max       16
_diffrn_reflns_limit_k_min       -16
_diffrn_reflns_limit_l_max       28
_diffrn_reflns_limit_l_min       -28
_diffrn_reflns_number            45436
_diffrn_reflns_theta_full        25.00
_diffrn_reflns_theta_max         25.00
_diffrn_reflns_theta_min         2.89
_diffrn_standards_decay_%        0
_diffrn_standards_interval_count n/a
_diffrn_standards_interval_time  n/a
_diffrn_standards_number         n/a
_exptl_absorpt_coefficient_mu    0.166
_exptl_absorpt_correction_type   Scalepack
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.310
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       plate
_exptl_crystal_F_000             5664
_exptl_crystal_size_max          0.4
_exptl_crystal_size_mid          0.3
_exptl_crystal_size_min          0.05
_refine_diff_density_max         0.506
_refine_diff_density_min         -0.407
_refine_diff_density_rms         0.073
_refine_ls_extinction_coef       0.00034(13)
_refine_ls_extinction_expression Fc^*^=kFc[1+0.001xFc^2^\l^3^/sin(2\q)]^-1/4^
_refine_ls_extinction_method     SHELXL
_refine_ls_goodness_of_fit_ref   1.071
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     820
_refine_ls_number_reflns         11181
_refine_ls_number_restraints     6
_refine_ls_restrained_S_all      1.070
_refine_ls_R_factor_all          0.1829
_refine_ls_R_factor_gt           0.1095
_refine_ls_shift/su_max          0.379
_refine_ls_shift/su_mean         0.006
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0880P)^2^+85.6717P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.2328
_refine_ls_wR_factor_ref         0.2683
_reflns_number_gt                6403
_reflns_number_total             11181
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            808492ksup1.cif
_cod_data_source_block           c3me
_cod_original_cell_volume        13569.4(17)
_cod_original_sg_symbol_H-M      C2/c
_cod_database_code               7110405