Concurrent display of both α- and β-turns in a model peptide.
Srinivas, Deekonda; Vijayadas, Kuruppanthara N.; Gonnade, Rajesh; Phalgune, Usha D.; Rajamohanan, Pattuparambil R.; Sanjayan, Gangadhar J.; Organic & biomolecular chemistry 9 (2011) 5762–5765; doi:10.1039/c1ob05553d

data_7151950
_publ_section_title
;
 Concurrent display of both \a- and \b-turns in a model peptide.
;
_journal_issue                   16
_journal_name_full               'Organic &amp; biomolecular chemistry'
_journal_page_first              5762
_journal_page_last               5765
_journal_paper_doi               10.1039/c1ob05553d
_journal_volume                  9
_journal_year                    2011
_chemical_absolute_configuration syn
_chemical_formula_moiety         'C18 H24 N4 O4'
_chemical_formula_sum            'C18 H24 N4 O4'
_chemical_formula_weight         360.41
_space_group_IT_number           4
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  'P 2yb'
_symmetry_space_group_name_H-M   'P 1 21 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                 100.076(4)
_cell_angle_gamma                90.00
_cell_formula_units_Z            2
_cell_length_a                   4.7957(14)
_cell_length_b                   19.605(6)
_cell_length_c                   9.913(3)
_cell_measurement_reflns_used    3211
_cell_measurement_temperature    297(2)
_cell_measurement_theta_max      26.63
_cell_measurement_theta_min      2.57
_cell_volume                     917.6(5)
_computing_cell_refinement       'BRUKER SAINT'
_computing_data_collection       'BRUKER SMART'
_computing_data_reduction        'BRUKER SAINT'
_computing_molecular_graphics    SHELXTL
_computing_publication_material  SHELXTL
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      297(2)
_diffrn_measured_fraction_theta_full 0.994
_diffrn_measured_fraction_theta_max 0.994
_diffrn_measurement_device       'Bruker Smart APEX'
_diffrn_measurement_device_type  'CCD Area Detector'
_diffrn_measurement_method       'Phi and Omega Scan'
_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  0.0163
_diffrn_reflns_av_sigmaI/netI    0.0199
_diffrn_reflns_limit_h_max       6
_diffrn_reflns_limit_h_min       -6
_diffrn_reflns_limit_k_max       25
_diffrn_reflns_limit_k_min       -25
_diffrn_reflns_limit_l_max       13
_diffrn_reflns_limit_l_min       -13
_diffrn_reflns_number            10080
_diffrn_reflns_theta_full        25.00
_diffrn_reflns_theta_max         25.00
_diffrn_reflns_theta_min         2.08
_exptl_absorpt_coefficient_mu    0.094
_exptl_absorpt_correction_T_max  0.983
_exptl_absorpt_correction_T_min  0.970
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   'bruker sadabs'
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.304
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       plate
_exptl_crystal_F_000             384
_exptl_crystal_size_max          0.76
_exptl_crystal_size_mid          0.27
_exptl_crystal_size_min          0.18
_refine_diff_density_max         0.269
_refine_diff_density_min         -0.195
_refine_diff_density_rms         0.040
_refine_ls_abs_structure_details 'Flack H D (1983), Acta Cryst. A39, 876-881'
_refine_ls_abs_structure_Flack   -0.5(13)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.070
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     248
_refine_ls_number_reflns         4092
_refine_ls_number_restraints     1
_refine_ls_restrained_S_all      1.070
_refine_ls_R_factor_all          0.0537
_refine_ls_R_factor_gt           0.0505
_refine_ls_shift/su_max          0.005
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0769P)^2^+0.1468P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1348
_refine_ls_wR_factor_ref         0.1377
_reflns_number_gt                3811
_reflns_number_total             4092
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            c1ob05553d.txt
_cod_data_source_block           dsbzp
_cod_depositor_comments
;
The following automatic conversions were performed:

'_symmetry_cell_setting' value 'Monoclinic' changed to 'monoclinic'
according to /home/saulius/struct/CIF-dictionaries/cif_core.dic
dictionary named 'cif_core.dic' version 2.4.1 from 2010-06-29.

Automatic conversion script
Id: cif_fix_values 1715 2011-07-08 13:25:40Z adriana 
;
_cod_original_cell_volume        917.7(5)
_cod_original_sg_symbol_H-M      P2(1)
_cod_database_code               7151950