Fluorine-hydrogen inter-actions observed in a helix structure having an orn-free gramicidin S sequence incorporating 4-<i>trans</i>-fluoro-proline.
Akiko, Asano; Sakata, Mizuki; Takuma, Kato; Doi, Mitsunobu; Acta crystallographica. Section E, Crystallographic communications 81 (2025) 345–349; doi:10.1107/S2056989025002592

data_2023453
_publ_section_title
;
 Fluorine-hydrogen inter-actions observed in a helix structure having an
 orn-free gramicidin S sequence incorporating
 4-<i>trans</i>-fluoro-proline.
;
_journal_coeditor_code           OX2013
_journal_issue                   'Pt 4'
_journal_name_full
'Acta crystallographica. Section E, Crystallographic communications'
_journal_page_first              345
_journal_page_last               349
_journal_paper_doi               10.1107/S2056989025002592
_journal_volume                  81
_journal_year                    2025
_chemical_absolute_configuration rm
_chemical_formula_iupac          'C68 H104 F2 N10 O13, C H4 O'
_chemical_formula_moiety         'C68 H104 F2 N10 O13, C H4 O'
_chemical_formula_sum            'C69 H108 F2 N10 O14'
_chemical_formula_weight         1339.65
_chemical_name_common
;
Boc-(<i>D</i>-Phe-tFPro-Val-Leu-Leu)~2~-OMe
;
_chemical_name_systematic
;
Boc-(<i>D</i>-Phe-tFPro-Val-Leu-Leu)~2~-OMe
;
_space_group_crystal_system      monoclinic
_space_group_IT_number           4
_space_group_name_Hall           'P 2yb'
_space_group_name_H-M_alt        'P 1 21 1'
_atom_sites_solution_hydrogens   geom
_audit_creation_method           SHELXL-2017/1
_cell_angle_alpha                90.0000(10)
_cell_angle_beta                 96.4840(10)
_cell_angle_gamma                90
_cell_formula_units_Z            2
_cell_length_a                   10.12480(10)
_cell_length_b                   28.72630(10)
_cell_length_c                   12.63780(10)
_cell_measurement_reflns_used    50791
_cell_measurement_temperature    100(2)
_cell_measurement_theta_max      73.4540
_cell_measurement_theta_min      4.4000
_cell_volume                     3652.17(5)
_computing_cell_refinement
;
CrysAlisPro 1.171.41.117a (Rigaku OD, 2015)
;
_computing_data_collection
;
CrysAlisPro 1.171.41.117a (Rigaku OD, 2015)
;
_computing_data_reduction
;
CrysAlisPro 1.171.41.117a (Rigaku OD, 2015)
;
_computing_molecular_graphics
;
Mercury (Macrae <i>et al.</i>,  2020 and <i>PyMol</i> (DeLano,
2002)
;
_computing_structure_refinement
;
<i>SHELXL2018/3</i> (Sheldrick, 2015b)
;
_computing_structure_solution
;
<i>SHELXT</i> (Sheldrick, 2015a)
;
_diffrn_ambient_temperature      100(2)
_diffrn_detector_area_resol_mean 5.8140
_diffrn_measured_fraction_theta_full 0.999
_diffrn_measured_fraction_theta_max 0.988
_diffrn_measurement_device_type  'XtaLAB AFC12 (RINC): Kappa single'
_diffrn_measurement_method       multi-scan
_diffrn_radiation_type           CuK\a
_diffrn_radiation_wavelength     1.54184
_diffrn_reflns_av_R_equivalents  0.0163
_diffrn_reflns_av_unetI/netI     0.0112
_diffrn_reflns_limit_h_max       12
_diffrn_reflns_limit_h_min       -12
_diffrn_reflns_limit_k_max       34
_diffrn_reflns_limit_k_min       -34
_diffrn_reflns_limit_l_max       15
_diffrn_reflns_limit_l_min       -15
_diffrn_reflns_number            66224
_diffrn_reflns_theta_full        67.684
_diffrn_reflns_theta_max         73.648
_diffrn_reflns_theta_min         3.520
_diffrn_source                   'Rotating-anode X-ray tube'
_exptl_absorpt_coefficient_mu    0.726
_exptl_absorpt_correction_T_max  1.00000
_exptl_absorpt_correction_T_min  0.90194
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details
;
(CrysAlisPro; Rigaku OD, 2015)
;
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    1.218
_exptl_crystal_description       recutangular
_exptl_crystal_F_000             1444
_exptl_crystal_size_max          0.200
_exptl_crystal_size_mid          0.200
_exptl_crystal_size_min          0.150
_refine_diff_density_max         0.171
_refine_diff_density_min         -0.212
_refine_ls_abs_structure_details
;
Flack <i>x</i> determined using 6582 quotients
[(<i>I</i>^+^)-(<i>I</i>^-^)]/[(<i>I</i>^+^)+(<i>I</i>^-^)]
(Parsons <i>et al.</i>,  2013)
;
_refine_ls_abs_structure_Flack   -0.003(16)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.022
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     858
_refine_ls_number_reflns         14120
_refine_ls_number_restraints     1
_refine_ls_restrained_S_all      1.022
_refine_ls_R_factor_all          0.0255
_refine_ls_R_factor_gt           0.0254
_refine_ls_shift/su_max          0.001
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w=1/[\s^2^(Fo^2^)+(0.0437P)^2^+0.5472P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0672
_refine_ls_wR_factor_ref         0.0673
_reflns_number_gt                14063
_reflns_number_total             14120
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            ox2013.cif
_cod_data_source_block           I
_cod_depositor_comments          'Adding full bibliography for 2023453.cif.'
_cod_original_sg_symbol_H-M      'P 21'
_cod_database_code               2023453
_shelx_estimated_absorpt_t_min   0.868
_shelx_estimated_absorpt_t_max   0.899
_shelx_hkl_checksum              20139
_shelx_res_checksum              85511