An exceptionally stable peptide nanotube system with flexible pores
Görbitz, Carl Henrik; Acta Crystallographica Section B 58 (2002) 849–854; doi:10.1107/S0108768102012314

data_2103453
_publ_section_title
;
 An exceptionally stable peptide nanotube system with flexible pores
;
_journal_issue                   5
_journal_name_full               'Acta Crystallographica Section B'
_journal_page_first              849
_journal_page_last               854
_journal_paper_doi               10.1107/S0108768102012314
_journal_volume                  58
_journal_year                    2002
_chemical_formula_sum            'C8 H16 N2 O3'
_chemical_formula_weight         188.23
_chemical_name_systematic
;
 L-Ala-L-Val
;
_space_group_IT_number           169
_symmetry_cell_setting           hexagonal
_symmetry_space_group_name_Hall  'P 61'
_symmetry_space_group_name_H-M   'P 61'
_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                 90.00
_cell_angle_gamma                120.00
_cell_formula_units_Z            6
_cell_length_a                   14.2957(3)
_cell_length_b                   14.2957(3)
_cell_length_c                   9.9077(2)
_cell_measurement_reflns_used    18212
_cell_measurement_temperature    150(2)
_cell_measurement_theta_max      37.00
_cell_measurement_theta_min      2.63
_cell_volume                     1753.53(6)
_computing_cell_refinement       'SAINT (Bruker, 1998)'
_computing_data_collection       'SMART (Bruker, 1998)'
_computing_data_reduction        'SAINT (Bruker, 1998)'
_computing_molecular_graphics    'SHELXTL (Sheldrick, 1997)'
_computing_publication_material  'SHELXTL (Sheldrick, 1997)'
_computing_structure_refinement  'SHELXTL (Sheldrick, 1997)'
_computing_structure_solution    'SHELXTL (Sheldrick, 1997)'
_diffrn_ambient_temperature      150(2)
_diffrn_detector_area_resol_mean 8.3
_diffrn_measured_fraction_theta_full 1.000
_diffrn_measured_fraction_theta_max 1.000
_diffrn_measurement_device_type  'Siemens SMART CCD diffractometer'
_diffrn_measurement_method
'Sets of exposures each taken over 0.3\% \w rotation'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'fine-focus sealed tube'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0274
_diffrn_reflns_av_sigmaI/netI    0.0193
_diffrn_reflns_limit_h_max       23
_diffrn_reflns_limit_h_min       -23
_diffrn_reflns_limit_k_max       24
_diffrn_reflns_limit_k_min       -24
_diffrn_reflns_limit_l_max       16
_diffrn_reflns_limit_l_min       -16
_diffrn_reflns_number            35248
_diffrn_reflns_theta_full        37.00
_diffrn_reflns_theta_max         37.00
_diffrn_reflns_theta_min         2.63
_diffrn_standards_decay_%        0
_exptl_absorpt_coefficient_mu    0.082
_exptl_absorpt_correction_T_max  0.976
_exptl_absorpt_correction_T_min  0.884
_exptl_absorpt_correction_type   empirical
_exptl_absorpt_process_details   'SADABS (Sheldrick, 1996)'
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.069
_exptl_crystal_density_meas      ?
_exptl_crystal_density_method    .
_exptl_crystal_description       needle
_exptl_crystal_F_000             612
_exptl_crystal_size_max          1.50
_exptl_crystal_size_mid          0.40
_exptl_crystal_size_min          0.30
_refine_diff_density_max         0.428
_refine_diff_density_min         -0.214
_refine_ls_abs_structure_details 'Flack H D (1983), Acta Cryst. A39, 876-881'
_refine_ls_abs_structure_Flack   0.1(5)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.042
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     141
_refine_ls_number_reflns         5946
_refine_ls_number_restraints     1
_refine_ls_restrained_S_all      1.042
_refine_ls_R_factor_all          0.0438
_refine_ls_R_factor_gt           0.0358
_refine_ls_shift/su_max          0.002
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0629P)^2^+0.0354P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0906
_refine_ls_wR_factor_ref         0.0952
_reflns_number_gt                5279
_reflns_number_total             5946
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            os0094.cif
_cod_data_source_block           2
_cod_original_cell_volume        1753.53(5)
_cod_database_code               2103453
_cod_database_fobs_code          2103453