Oligopeptides with Equal Amounts of l- and d-Amino Acids May Prefer a Helix Screw Sense
Yosuke Demizu; Hiroko Yamashita; Norikazu Yamazaki; Yukiko Sato; Mitsunobu Doi; Masakazu Tanaka; Masaaki Kurihara; Journal of Organic Chemistry 78 (2013) 12106–12113; doi:10.1021/jo402133e

data_4028831
_publ_contact_author_email       demizu@nihs.go.jp
_publ_contact_author_fax         +81-3-3707-6950
_publ_contact_author_name        'Yosuke Demizu Ph.D'
_publ_contact_author_phone       +81-3-3700-1141
_publ_section_title
;
 Oligopeptides with Equal Amounts of l- and d-Amino Acids May Prefer a
 Helix Screw Sense
;
_journal_name_full               'Journal of Organic Chemistry'
_journal_page_first              12106
_journal_page_last               12113
_journal_paper_doi               10.1021/jo402133e
_journal_volume                  78
_journal_year                    2013
_chemical_absolute_configuration rm
_chemical_compound_source        synthesis
_chemical_formula_moiety         'C70 H128 N12 O15, 2.48(C4 H8 O2), 2(H2 O)'
_chemical_formula_sum            'C79.92 H151.84 N12 O21.96'
_chemical_formula_weight         1632.38
_chemical_name_systematic
; 
 Boc-(Leu-D-Leu-Aib)4-OMe.2H2O.2.48C4H8O2
;
_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                   14.9724(15)
_cell_length_b                   16.2335(17)
_cell_length_c                   38.546(4)
_cell_measurement_reflns_used    9197
_cell_measurement_temperature    90(2)
_cell_measurement_theta_max      23.30
_cell_measurement_theta_min      2.44
_cell_volume                     9368.8(17)
_computing_cell_refinement       'SAINTPLUS (Bruker, 1998)'
_computing_data_collection       'SMART (Bruker, 1998)'
_computing_data_reduction        'SAINTPLUS (Bruker, 1998)'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 2008)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 2008)'
_diffrn_ambient_temperature      90(2)
_diffrn_detector_area_resol_mean 8.366
_diffrn_measured_fraction_theta_full 0.999
_diffrn_measured_fraction_theta_max 0.999
_diffrn_measurement_device_type  'CCD (Bruker APEX)'
_diffrn_measurement_method       \w-scan
_diffrn_radiation_monochromator  'conforcal (Bruker Montel)'
_diffrn_radiation_source         'rotating anode (M18XCE)'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0437
_diffrn_reflns_av_sigmaI/netI    0.0448
_diffrn_reflns_limit_h_max       19
_diffrn_reflns_limit_h_min       -19
_diffrn_reflns_limit_k_max       20
_diffrn_reflns_limit_k_min       -20
_diffrn_reflns_limit_l_max       49
_diffrn_reflns_limit_l_min       -49
_diffrn_reflns_number            81960
_diffrn_reflns_theta_full        27.10
_diffrn_reflns_theta_max         27.10
_diffrn_reflns_theta_min         1.06
_diffrn_standards_decay_%        0.0
_diffrn_standards_interval_count 81960
_diffrn_standards_interval_time  900
_diffrn_standards_number         484
_exptl_absorpt_coefficient_mu    0.084
_exptl_absorpt_correction_T_max  1.064
_exptl_absorpt_correction_T_min  0.954
_exptl_absorpt_correction_type   empirical
_exptl_absorpt_process_details   'SADABS (Sheldrick, 1996)'
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.159
_exptl_crystal_description       block
_exptl_crystal_F_000             3568
_exptl_crystal_size_max          0.30
_exptl_crystal_size_mid          0.30
_exptl_crystal_size_min          0.20
_refine_diff_density_max         0.921
_refine_diff_density_min         -0.359
_refine_diff_density_rms         0.061
_refine_ls_abs_structure_details 'Flack (1983), 9414 Friedel pairs'
_refine_ls_abs_structure_Flack   0.4(9)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.045
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     1183
_refine_ls_number_reflns         20643
_refine_ls_number_restraints     105
_refine_ls_restrained_S_all      1.062
_refine_ls_R_factor_all          0.0840
_refine_ls_R_factor_gt           0.0683
_refine_ls_shift/su_max          0.015
_refine_ls_shift/su_mean         0.001
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0921P)^2^+7.4707P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1776
_refine_ls_wR_factor_ref         0.1881
_reflns_number_gt                17001
_reflns_number_total             20643
_reflns_threshold_expression     I>2\s(I)
_cod_data_source_file            jo402133e_si_003.cif
_cod_data_source_block           lda4
_cod_database_code               4028831