Left-Handed Helical Preference in an Achiral Peptide Chain Is Induced by an l-Amino Acid in an N-Terminal Type II β-Turn
Matteo De Poli; Marta De Zotti; James Raftery; Juan A. Aguilar; Gareth A. Morris; Jonathan Clayden; Journal of Organic Chemistry 78 (2013) 2248–2255; doi:10.1021/jo302705k

data_4028041
_publ_section_title
;
 Left-Handed Helical Preference in an Achiral Peptide Chain Is Induced by
 an l-Amino Acid in an N-Terminal Type II \b-Turn
;
_journal_name_full               'Journal of Organic Chemistry'
_journal_page_first              2248
_journal_page_last               2255
_journal_paper_doi               10.1021/jo302705k
_journal_volume                  78
_journal_year                    2013
_chemical_absolute_configuration syn
_chemical_formula_moiety         'C27 H49 N5 O7, H2 O'
_chemical_formula_sum            'C27 H51 N5 O8'
_chemical_formula_weight         573.73
_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                 94.202(3)
_cell_angle_gamma                90.00
_cell_formula_units_Z            2
_cell_length_a                   9.2540(14)
_cell_length_b                   17.036(3)
_cell_length_c                   10.3534(16)
_cell_measurement_reflns_used    803
_cell_measurement_temperature    100(2)
_cell_measurement_theta_max      20.64
_cell_measurement_theta_min      2.31
_cell_volume                     1627.8(5)
_computing_cell_refinement       'Bruker SMART'
_computing_data_collection       'Bruker SMART'
_computing_data_reduction        'Bruker SAINT'
_computing_molecular_graphics    'Bruker SHELXTL'
_computing_publication_material  'Bruker SHELXTL'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      100(2)
_diffrn_measured_fraction_theta_full 0.993
_diffrn_measured_fraction_theta_max 0.993
_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  0.0419
_diffrn_reflns_av_sigmaI/netI    0.1096
_diffrn_reflns_limit_h_max       11
_diffrn_reflns_limit_h_min       -11
_diffrn_reflns_limit_k_max       21
_diffrn_reflns_limit_k_min       -21
_diffrn_reflns_limit_l_max       9
_diffrn_reflns_limit_l_min       -12
_diffrn_reflns_number            9507
_diffrn_reflns_theta_full        26.37
_diffrn_reflns_theta_max         26.37
_diffrn_reflns_theta_min         1.97
_exptl_absorpt_coefficient_mu    0.086
_exptl_absorpt_correction_type   none
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.171
_exptl_crystal_description       plate
_exptl_crystal_F_000             624
_exptl_crystal_size_max          0.60
_exptl_crystal_size_mid          0.20
_exptl_crystal_size_min          0.06
_refine_diff_density_max         0.201
_refine_diff_density_min         -0.179
_refine_diff_density_rms         0.040
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   0.831
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     396
_refine_ls_number_reflns         6068
_refine_ls_number_restraints     1
_refine_ls_restrained_S_all      0.831
_refine_ls_R_factor_all          0.0727
_refine_ls_R_factor_gt           0.0490
_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^)+(0.0089P)^2^+0.0000P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0639
_refine_ls_wR_factor_ref         0.0694
_reflns_number_gt                4417
_reflns_number_total             6068
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            jo302705k_si_001.cif
_cod_data_source_block           s3611m
_cod_original_cell_volume        1627.8(4)
_cod_original_sg_symbol_Hall     P2yb
_cod_database_code               4028041