Peptide α/310-Helix Dimorphism in the Crystal State
Marco Crisma; Michele Saviano; Alessandro Moretto; Quirinus B. Broxterman; Bernard Kaptein; Claudio Toniolo; Journal of the American Chemical Society 129 (2007) 15471–15473; doi:10.1021/ja076656a

data_4110298
_publ_section_title
;
 Peptide \a/310-Helix Dimorphism in the Crystal State
;
_journal_name_full               'Journal of the American Chemical Society'
_journal_page_first              15471
_journal_page_last               15473
_journal_paper_doi               10.1021/ja076656a
_journal_volume                  129
_journal_year                    2007
_chemical_formula_sum            'C47 H88 N8 O8'
_chemical_formula_weight         893.25
_chemical_name_systematic
;
 Ac-[L-(\aMe)Val]7-NHiPr
;
_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                 110.95(4)
_cell_angle_gamma                90.00
_cell_formula_units_Z            6
_cell_length_a                   24.512(6)
_cell_length_b                   10.257(2)
_cell_length_c                   34.311(9)
_cell_measurement_reflns_used    3266
_cell_measurement_temperature    293(2)
_cell_measurement_theta_max      27.0837
_cell_measurement_theta_min      1.3709
_cell_volume                     8056(4)
_computing_cell_refinement       'CrystalClear (Rigaku/MSC Inc., 2006)'
_computing_data_collection       'CrystalClear (Rigaku/MSC Inc., 2006)'
_computing_data_reduction        'CrystalClear (Rigaku/MSC Inc., 2006)'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SIR2002 (Burla et al., 2003)'
_diffrn_ambient_temperature      295(2)
_diffrn_detector_area_resol_mean 22.2222
_diffrn_measured_fraction_theta_full 0.952
_diffrn_measured_fraction_theta_max 0.952
_diffrn_measurement_device_type  'Rigaku Saturn 944 CCD'
_diffrn_measurement_method       'Omega rotation'
_diffrn_radiation_monochromator  Confocal
_diffrn_radiation_source         'Rotating Anode'
_diffrn_radiation_type           CuK\a
_diffrn_radiation_wavelength     1.54178
_diffrn_reflns_av_R_equivalents  0.0752
_diffrn_reflns_av_sigmaI/netI    0.0875
_diffrn_reflns_limit_h_max       24
_diffrn_reflns_limit_h_min       -23
_diffrn_reflns_limit_k_max       7
_diffrn_reflns_limit_k_min       -10
_diffrn_reflns_limit_l_max       34
_diffrn_reflns_limit_l_min       -33
_diffrn_reflns_number            39600
_diffrn_reflns_theta_full        50.43
_diffrn_reflns_theta_max         50.43
_diffrn_reflns_theta_min         1.38
_exptl_absorpt_coefficient_mu    0.603
_exptl_absorpt_correction_T_max  1.0000
_exptl_absorpt_correction_T_min  0.6393
_exptl_absorpt_correction_type   multi-scan
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.105
_exptl_crystal_description       plate
_exptl_crystal_F_000             2940
_exptl_crystal_size_max          0.15
_exptl_crystal_size_mid          0.15
_exptl_crystal_size_min          0.04
_refine_diff_density_max         0.534
_refine_diff_density_min         -0.380
_refine_diff_density_rms         0.072
_refine_ls_abs_structure_details 'Flack H D (1983), Acta Cryst. A39, 876-881'
_refine_ls_abs_structure_Flack   0.4(4)
_refine_ls_extinction_coef       0.0033(5)
_refine_ls_extinction_expression Fc^*^=kFc[1+0.001xFc^2^\l^3^/sin(2\q)]^-1/4^
_refine_ls_extinction_method     SHELXL
_refine_ls_goodness_of_fit_ref   1.411
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           fullcycle
_refine_ls_number_parameters     1703
_refine_ls_number_reflns         13308
_refine_ls_number_restraints     235
_refine_ls_restrained_S_all      1.416
_refine_ls_R_factor_all          0.1590
_refine_ls_R_factor_gt           0.1212
_refine_ls_shift/su_max          0.087
_refine_ls_shift/su_mean         0.017
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.1820P)^2^+0.0000P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.3041
_refine_ls_wR_factor_ref         0.3649
_reflns_number_gt                9216
_reflns_number_total             13308
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            ja076656a-file002.cif
_cod_data_source_block           mc111na
_cod_original_cell_volume        8056(3)
_cod_database_code               4110298