Multiple Conformational States in Crystals and in Solution in αγ Hybrid Peptides. Fragility of the C~12~ Helix in Short Sequences
Sunanda Chatterjee; Prema G. Vasudev; Kuppanna Ananda; Srinivasarao Raghothama; Narayanaswamy Shamala; Padmanabhan Balaram; Journal of Organic Chemistry 73 (2008) 6595–6606; doi:10.1021/jo8009819

data_4023640
_publ_section_title
;
 Multiple Conformational States in Crystals and in Solution in \a\g
 Hybrid Peptides. Fragility of the C~12~ Helix in Short Sequences
;
_journal_name_full               'Journal of Organic Chemistry'
_journal_page_first              6595
_journal_page_last               6606
_journal_paper_doi               10.1021/jo8009819
_journal_volume                  73
_journal_year                    2008
_chemical_formula_moiety         'C32 H57 N5 O6 + H2O + 0.25*CH3OH'
_chemical_formula_sum            'C32.25 H59 N5 O7.25'
_chemical_formula_weight         632.84
_chemical_name_common            Boc-Aib-Gpn-Aib-Gpn-NHMe
_space_group_IT_number           14
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  '-P 2ybc'
_symmetry_space_group_name_H-M   'P 1 21/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                 105.4160(10)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   14.4622(10)
_cell_length_b                   13.1789(9)
_cell_length_c                   20.3222(15)
_cell_measurement_temperature    293(2)
_cell_volume                     3734.0(5)
_computing_data_collection       SMART
_computing_data_reduction        SAINT
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      293(2)
_diffrn_measured_fraction_theta_full 0.919
_diffrn_measured_fraction_theta_max 0.919
_diffrn_measurement_device_type  'BRUKER AXS SMART APEX CCD with Mo source'
_diffrn_measurement_method       '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  0.0226
_diffrn_reflns_av_sigmaI/netI    0.0212
_diffrn_reflns_limit_h_max       17
_diffrn_reflns_limit_h_min       -16
_diffrn_reflns_limit_k_max       16
_diffrn_reflns_limit_k_min       -16
_diffrn_reflns_limit_l_max       24
_diffrn_reflns_limit_l_min       -25
_diffrn_reflns_number            27608
_diffrn_reflns_theta_full        26.82
_diffrn_reflns_theta_max         26.82
_diffrn_reflns_theta_min         1.86
_exptl_absorpt_coefficient_mu    0.079
_exptl_absorpt_correction_type   none
_exptl_crystal_colour            Colorless
_exptl_crystal_density_diffrn    1.126
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       Clear
_exptl_crystal_F_000             1382
_exptl_crystal_size_max          0.60
_exptl_crystal_size_mid          0.50
_exptl_crystal_size_min          0.14
_refine_diff_density_max         0.347
_refine_diff_density_min         -0.163
_refine_diff_density_rms         0.035
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.019
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     443
_refine_ls_number_reflns         7362
_refine_ls_number_restraints     1
_refine_ls_restrained_S_all      1.021
_refine_ls_R_factor_all          0.0712
_refine_ls_R_factor_gt           0.0498
_refine_ls_shift/su_max          0.026
_refine_ls_shift/su_mean         0.001
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0763P)^2^+0.8004P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1316
_refine_ls_wR_factor_ref         0.1479
_reflns_number_gt                5348
_reflns_number_total             7362
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            jo8009819-file004.cif
_cod_data_source_block           2b
_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.

'_exptl_absorpt_correction_type' value 'None' changed to
'none' 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_enum 1527 2010-12-29 10:47:43Z saulius 
;
_cod_original_sg_symbol_H-M      'P 21/c'
_cod_database_code               4023640