Supramolecular double helix from capped ?-peptide
Suman Maity; Sibaprasad Maity; Poulami Jana; Debasish Haldar; Chem.Commun. 48 (2012) 711–; doi:10.1039/c1cc15570a

data_7107173
_publ_section_title
;
 Supramolecular double helix from capped ?-peptide
;
_journal_name_full               Chem.Commun.
_journal_page_first              711
_journal_paper_doi               10.1039/c1cc15570a
_journal_volume                  48
_journal_year                    2012
_chemical_formula_moiety         'C25 H37 N3 O4'
_chemical_formula_sum            'C25 H37 N3 O4'
_chemical_formula_weight         443.5790
_space_group_IT_number           2
_symmetry_cell_setting           triclinic
_symmetry_space_group_name_Hall  '-P 1'
_symmetry_space_group_name_H-M   'P -1'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL-97
_cell_angle_alpha                91.506(4)
_cell_angle_beta                 95.452(4)
_cell_angle_gamma                90.632(4)
_cell_formula_units_Z            4
_cell_length_a                   12.4834(8)
_cell_length_b                   13.8403(9)
_cell_length_c                   14.9746(10)
_cell_measurement_reflns_used    7677
_cell_measurement_temperature    296(2)
_cell_measurement_theta_max      17.57
_cell_measurement_theta_min      2.19
_cell_volume                     2574.4(3)
_computing_cell_refinement       'Bruker SMART'
_computing_data_collection       'Bruker SMART'
_computing_data_reduction        'Bruker SAINT'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      296(2)
_diffrn_measured_fraction_theta_full 0.979
_diffrn_measured_fraction_theta_max 0.979
_diffrn_measurement_device_type  'CCD area detector'
_diffrn_measurement_method       'phi and omega scans'
_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  0.0439
_diffrn_reflns_av_sigmaI/netI    0.0303
_diffrn_reflns_limit_h_max       10
_diffrn_reflns_limit_h_min       -10
_diffrn_reflns_limit_k_max       11
_diffrn_reflns_limit_k_min       -11
_diffrn_reflns_limit_l_max       12
_diffrn_reflns_limit_l_min       -12
_diffrn_reflns_number            16204
_diffrn_reflns_theta_full        17.60
_diffrn_reflns_theta_max         17.60
_diffrn_reflns_theta_min         1.37
_exptl_absorpt_coefficient_mu    0.077
_exptl_absorpt_correction_type   none
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.137
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       block
_exptl_crystal_F_000             960.0
_exptl_crystal_size_max          0.92
_exptl_crystal_size_mid          0.57
_exptl_crystal_size_min          0.21
_refine_diff_density_max         0.273
_refine_diff_density_min         -0.177
_refine_diff_density_rms         0.036
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   0.981
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     583
_refine_ls_number_reflns         3248
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      0.981
_refine_ls_R_factor_all          0.0661
_refine_ls_R_factor_gt           0.0541
_refine_ls_shift/su_max          0.003
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0971P)^2^+3.7187P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1528
_refine_ls_wR_factor_ref         0.1700
_reflns_number_gt                2678
_reflns_number_total             3248
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            c1cc15570a.txt
_cod_data_source_block           sm1
_cod_original_sg_symbol_H-M      P-1
_cod_database_code               7107173