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_7151951
_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         'C21 H37 N5 O7 . H2O'
_chemical_formula_sum            'C21 H39 N5 O8'
_chemical_formula_weight         489.57
_space_group_IT_number           19
_symmetry_cell_setting           orthorhombic
_symmetry_space_group_name_Hall  'P 2ac 2ab'
_symmetry_space_group_name_H-M   'P 21 21 21'
_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                90.00
_cell_formula_units_Z            4
_cell_length_a                   9.056(5)
_cell_length_b                   9.842(4)
_cell_length_c                   29.153(17)
_cell_measurement_reflns_used    1533
_cell_measurement_temperature    297(2)
_cell_measurement_theta_max      18.64
_cell_measurement_theta_min      2.49
_cell_volume                     2598(2)
_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 0.998
_diffrn_measured_fraction_theta_max 0.998
_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  0.0827
_diffrn_reflns_av_sigmaI/netI    0.0807
_diffrn_reflns_limit_h_max       10
_diffrn_reflns_limit_h_min       -10
_diffrn_reflns_limit_k_max       10
_diffrn_reflns_limit_k_min       -11
_diffrn_reflns_limit_l_max       34
_diffrn_reflns_limit_l_min       -32
_diffrn_reflns_number            15967
_diffrn_reflns_theta_full        25.00
_diffrn_reflns_theta_max         25.00
_diffrn_reflns_theta_min         1.40
_exptl_absorpt_coefficient_mu    0.096
_exptl_absorpt_correction_T_max  0.9981
_exptl_absorpt_correction_T_min  0.9653
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   'bruker sadabs'
_exptl_crystal_colour            COLOURLESS
_exptl_crystal_density_diffrn    1.252
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       'THIN PLATE'
_exptl_crystal_F_000             1056
_exptl_crystal_size_max          0.37
_exptl_crystal_size_mid          0.27
_exptl_crystal_size_min          0.02
_refine_diff_density_max         0.188
_refine_diff_density_min         -0.206
_refine_diff_density_rms         0.041
_refine_ls_abs_structure_details 'Flack H D (1983), Acta Cryst. A39, 876-881'
_refine_ls_abs_structure_Flack   1(2)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.083
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     347
_refine_ls_number_reflns         4566
_refine_ls_number_restraints     2
_refine_ls_restrained_S_all      1.083
_refine_ls_R_factor_all          0.1032
_refine_ls_R_factor_gt           0.0711
_refine_ls_shift/su_max          0.001
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0452P)^2^+0.8291P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1383
_refine_ls_wR_factor_ref         0.1512
_reflns_number_gt                3295
_reflns_number_total             4566
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            c1ob05553d.txt
_cod_data_source_block           shrini1
_cod_depositor_comments
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The following automatic conversions were performed:

'_symmetry_cell_setting' value 'Orthorhombic' changed to
'orthorhombic' 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_sg_symbol_H-M      P2(1)2(1)2(1)
_cod_database_code               7151951